title: Antivirus Relevant File Paths Alerts
id: c9a88268-0047-4824-ba6e-4d81ce0b907c
status: test
description: |
    Detects an Antivirus alert in a highly relevant file path or with a relevant file name.
    This event must not be ignored just because the AV has blocked the malware but investigate, how it came there in the first place.
references:
    - https://www.nextron-systems.com/?s=antivirus
author: Florian Roth (Nextron Systems), Arnim Rupp
date: 2018-09-09
modified: 2024-11-02
tags:
    - attack.resource-development
    - attack.t1588
logsource:
    category: antivirus
detection:
    selection_path:
        Filename|contains:
            - ':\PerfLogs\'
            - ':\Temp\'
            - ':\Users\Default\'
            - ':\Users\Public\'
            - ':\Windows\'
            - '/www/'
            # - '\Client\'
            - '\inetpub\'
            - '\tsclient\'
            - 'apache'
            - 'nginx'
            - 'tomcat'
            - 'weblogic'
    selection_ext:
        Filename|endswith:
            - '.asax'
            - '.ashx'
            - '.asmx'
            - '.asp'
            - '.aspx'
            - '.bat'
            - '.cfm'
            - '.cgi'
            - '.chm'
            - '.cmd'
            - '.dat'
            - '.ear'
            - '.gif'
            - '.hta'
            - '.jpeg'
            - '.jpg'
            - '.jsp'
            - '.jspx'
            - '.lnk'
            - '.msc'
            - '.php'
            - '.pl'
            - '.png'
            - '.ps1'
            - '.psm1'
            - '.py'
            - '.pyc'
            - '.rb'
            - '.scf'
            - '.sct'
            - '.sh'
            - '.svg'
            - '.txt'
            - '.vbe'
            - '.vbs'
            - '.war'
            - '.wll'
            - '.wsf'
            - '.wsh'
            - '.xll'
            - '.xml'
    condition: 1 of selection_*
falsepositives:
    - Unlikely
level: high

title: Antivirus Hacktool Detection
id: fa0c05b6-8ad3-468d-8231-c1cbccb64fba
status: stable
description: |
    Detects a highly relevant Antivirus alert that reports a hack tool or other attack tool.
    This event must not be ignored just because the AV has blocked the malware but investigate, how it came there in the first place.
references:
    - https://www.nextron-systems.com/2021/08/16/antivirus-event-analysis-cheat-sheet-v1-8-2/
    - https://www.nextron-systems.com/?s=antivirus
author: Florian Roth (Nextron Systems), Arnim Rupp
date: 2021-08-16
modified: 2024-11-02
tags:
    - attack.execution
    - attack.t1204
logsource:
    category: antivirus
detection:
    selection:
        - Signature|startswith:
              - 'ATK/'  # Sophos
              - 'Exploit.Script.CVE'
              - 'HKTL'
              - 'HTOOL'
              - 'PWS.'
              - 'PWSX'
              - 'SecurityTool'
              # - 'FRP.'
        - Signature|contains:
              - 'Adfind'
              - 'Brutel'
              - 'BruteR'
              - 'Cobalt'
              - 'COBEACON'
              - 'Cometer'
              - 'DumpCreds'
              - 'FastReverseProxy'
              - 'Hacktool'
              - 'Havoc'
              - 'Impacket'
              - 'Keylogger'
              - 'Koadic'
              - 'Mimikatz'
              - 'Nighthawk'
              - 'PentestPowerShell'
              - 'Potato'
              - 'PowerSploit'
              - 'PowerSSH'
              - 'PshlSpy'
              - 'PSWTool'
              - 'PWCrack'
              - 'PWDump'
              - 'Rozena'
              - 'Rusthound'
              - 'Sbelt'
              - 'Seatbelt'
              - 'SecurityTool'
              - 'SharpDump'
              - 'SharpHound'
              - 'Shellcode'
              - 'Sliver'
              - 'Snaffler'
              - 'SOAPHound'
              - 'Splinter'
              - 'Swrort'
              - 'TurtleLoader'
    condition: selection
falsepositives:
    - Unlikely
level: high

title: Communication To LocaltoNet Tunneling Service Initiated - Linux
id: c4568f5d-131f-4e78-83d4-45b2da0ec4f1
status: test
description: |
    Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains.
    LocaltoNet is a reverse proxy that enables localhost services to be exposed to the Internet.
    Attackers have been seen to use this service for command-and-control activities to bypass MFA and perimeter controls.
references:
    - https://localtonet.com/documents/supported-tunnels
    - https://cloud.google.com/blog/topics/threat-intelligence/unc3944-targets-saas-applications
author: Andreas Braathen (mnemonic.io)
date: 2024-06-17
tags:
    - attack.command-and-control
    - attack.t1572
    - attack.t1090
    - attack.t1102
logsource:
    category: network_connection
    product: linux
detection:
    selection:
        DestinationHostname|endswith:
            - '.localto.net'
            - '.localtonet.com'
        Initiated: 'true'
    condition: selection
falsepositives:
    - Legitimate use of the LocaltoNet service.
level: high

title: Potentially Suspicious Malware Callback Communication - Linux
id: dbfc7c98-04ab-4ab7-aa94-c74d22aa7376
related:
    - id: 4b89abaa-99fe-4232-afdd-8f9aa4d20382
      type: derived
status: test
description: |
    Detects programs that connect to known malware callback ports based on threat intelligence reports.
references:
    - https://www.mandiant.com/resources/blog/triton-actor-ttp-profile-custom-attack-tools-detections
    - https://www.mandiant.com/resources/blog/ukraine-and-sandworm-team
    - https://www.elastic.co/guide/en/security/current/potential-non-standard-port-ssh-connection.html
    - https://thehackernews.com/2024/01/systembc-malwares-c2-server-analysis.html
    - https://www.cybereason.com/blog/sliver-c2-leveraged-by-many-threat-actors
author: hasselj
date: 2024-05-10
tags:
    - attack.persistence
    - attack.command-and-control
    - attack.t1571
logsource:
    category: network_connection
    product: linux
detection:
    selection:
        Initiated: 'true'
        DestinationPort:
            - 888
            - 999
            - 2200
            - 2222
            - 4000
            - 4444
            - 6789
            - 8531
            - 50501
            - 51820
    filter_main_local_ranges:
        DestinationIp|cidr:
            - '127.0.0.0/8'
            - '10.0.0.0/8'
            - '172.16.0.0/12'
            - '192.168.0.0/16'
            - '169.254.0.0/16'
            - '::1/128'         # IPv6 loopback
            - 'fe80::/10'       # IPv6 link-local addresses
            - 'fc00::/7'        # IPv6 private addresses
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

title: Communication To Ngrok Tunneling Service - Linux
id: 19bf6fdb-7721-4f3d-867f-53467f6a5db6
status: test
description: Detects an executable accessing an ngrok tunneling endpoint, which could be a sign of forbidden exfiltration of data exfiltration by malicious actors
references:
    - https://twitter.com/hakluke/status/1587733971814977537/photo/1
    - https://ngrok.com/docs/secure-tunnels/tunnels/ssh-reverse-tunnel-agent
author: Florian Roth (Nextron Systems)
date: 2022-11-03
tags:
    - attack.exfiltration
    - attack.command-and-control
    - attack.t1567
    - attack.t1568.002
    - attack.t1572
    - attack.t1090
    - attack.t1102
    - attack.s0508
logsource:
    product: linux
    category: network_connection
detection:
    selection:
        DestinationHostname|contains:
            - 'tunnel.us.ngrok.com'
            - 'tunnel.eu.ngrok.com'
            - 'tunnel.ap.ngrok.com'
            - 'tunnel.au.ngrok.com'
            - 'tunnel.sa.ngrok.com'
            - 'tunnel.jp.ngrok.com'
            - 'tunnel.in.ngrok.com'
    condition: selection
falsepositives:
    - Legitimate use of ngrok
level: high

title: Shell Execution GCC  - Linux
id: 9b5de532-a757-4d70-946c-1f3e44f48b4d
status: test
description: |
    Detects the use of the "gcc" utility to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/gcc/#shell
    - https://gtfobins.github.io/gtfobins/c89/#shell
    - https://gtfobins.github.io/gtfobins/c99/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith:
            - '/c89'
            - '/c99'
            - '/gcc'
        CommandLine|contains: '-wrapper'
    selection_cli:
        CommandLine|contains:
            - '/bin/bash,-s'
            - '/bin/dash,-s'
            - '/bin/fish,-s'
            - '/bin/sh,-s'
            - '/bin/zsh,-s'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

title: Shell Execution via Rsync - Linux
id: e2326866-609f-4015-aea9-7ec634e8aa04
status: experimental
description: |
    Detects the use of the "rsync" utility to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/rsync/#shell
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.), Florian Roth
date: 2024-09-02
modified: 2025-01-18
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith:
            - '/rsync'
            - '/rsyncd'
        CommandLine|contains: ' -e '
    selection_cli:
        CommandLine|contains:
            - '/ash '
            - '/bash '
            - '/dash '
            - '/csh '
            - '/sh '
            - '/zsh '
            - '/tcsh '
            - '/ksh '
            - "'ash "
            - "'bash "
            - "'dash "
            - "'csh "
            - "'sh "
            - "'zsh "
            - "'tcsh "
            - "'ksh "
    condition: all of selection_*
falsepositives:
    - Legitimate cases in which "rsync" is used to execute a shell
level: high

title: Shell Execution via Git - Linux
id: 47b3bbd4-1bf7-48cc-84ab-995362aaa75a
status: test
description: |
    Detects the use of the "git" utility to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/git/#shell
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        ParentImage|endswith: '/git'
        ParentCommandLine|contains|all:
            - ' -p '
            - 'help'
        CommandLine|contains:
            - 'bash 0<&1'
            - 'dash 0<&1'
            - 'sh 0<&1'
    condition: selection
falsepositives:
    - Unknown
level: high

title: Suspicious Invocation of Shell via Rsync
id: 297241f3-8108-4b3a-8c15-2dda9f844594
status: experimental
description: |
    Detects the execution of a shell as sub process of "rsync" without the expected command line flag "-e" being used, which could be an indication of exploitation as described in CVE-2024-12084. This behavior is commonly associated with attempts to execute arbitrary commands or escalate privileges, potentially leading to unauthorized access or further exploitation.
references:
    - https://sysdig.com/blog/detecting-and-mitigating-cve-2024-12084-rsync-remote-code-execution/
    - https://gist.github.com/Neo23x0/a20436375a1e26524931dd8ea1a3af10
author: Florian Roth
date: 2025-01-18
tags:
    - attack.execution
    - attack.t1059
    - attack.t1203
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        ParentImage|endswith:
            - '/rsync'
            - '/rsyncd'
        Image|endswith:
            - '/ash'
            - '/bash'
            - '/csh'
            - '/dash'
            - '/ksh'
            - '/sh'
            - '/tcsh'
            - '/zsh'
    filter_main_expected:
        CommandLine|contains: ' -e '
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

title: ESXi Admin Permission Assigned To Account Via ESXCLI
id: 9691f58d-92c1-4416-8bf3-2edd753ec9cf
status: test
description: Detects execution of the "esxcli" command with the "system" and "permission" flags in order to assign admin permissions to an account.
references:
    - https://developer.broadcom.com/xapis/esxcli-command-reference/7.0.0/namespace/esxcli_system.html
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-09-04
tags:
    - attack.persistence
    - attack.execution
    - attack.privilege-escalation
    - attack.t1059.012
    - attack.t1098
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/esxcli'
        CommandLine|contains: 'system'
        CommandLine|contains|all:
            - ' permission '
            - ' set'
            - 'Admin'
    condition: selection
falsepositives:
    - Legitimate administration activities
level: high

title: Capsh Shell Invocation - Linux
id: db1ac3be-f606-4e3a-89e0-9607cbe6b98a
status: test
description: |
    Detects the use of the "capsh" utility to invoke a shell.
references:
    - https://gtfobins.github.io/gtfobins/capsh/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/capsh'
        CommandLine|endswith: ' --'
    condition: selection
falsepositives:
    - Unknown
level: high

title: Inline Python Execution - Spawn Shell Via OS System Library
id: 2d2f44ff-4611-4778-a8fc-323a0e9850cc
status: test
description: |
    Detects execution of inline Python code via the "-c" in order to call the "system" function from the "os" library, and spawn a shell.
references:
    - https://gtfobins.github.io/gtfobins/python/#shell
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        - Image|endswith:
              - '/python'
              - '/python2'
              - '/python3'
        - Image|contains:
              - '/python2.'  # python image is always of the form ../python3.10; ../python is just a symlink
              - '/python3.'
    selection_cli:
        CommandLine|contains|all:
            - ' -c '
            - 'os.system('
        CommandLine|contains:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

title: Potential Netcat Reverse Shell Execution
id: 7f734ed0-4f47-46c0-837f-6ee62505abd9
status: test
description: Detects execution of netcat with the "-e" flag followed by common shells. This could be a sign of a potential reverse shell setup.
references:
    - https://pentestmonkey.net/cheat-sheet/shells/reverse-shell-cheat-sheet
    - https://www.revshells.com/
    - https://www.hackingtutorials.org/networking/hacking-netcat-part-2-bind-reverse-shells/
    - https://www.infosecademy.com/netcat-reverse-shells/
    - https://man7.org/linux/man-pages/man1/ncat.1.html
author: '@d4ns4n_, Nasreddine Bencherchali (Nextron Systems)'
date: 2023-04-07
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection_nc:
        Image|endswith:
            - '/nc'
            - '/ncat'
    selection_flags:
        CommandLine|contains:
            - ' -c '
            - ' -e '
    selection_shell:
        CommandLine|contains:
            - ' ash'
            - ' bash'
            - ' bsh'
            - ' csh'
            - ' ksh'
            - ' pdksh'
            - ' sh'
            - ' tcsh'
            - '/bin/ash'
            - '/bin/bash'
            - '/bin/bsh'
            - '/bin/csh'
            - '/bin/ksh'
            - '/bin/pdksh'
            - '/bin/sh'
            - '/bin/tcsh'
            - '/bin/zsh'
            - '$IFSash'
            - '$IFSbash'
            - '$IFSbsh'
            - '$IFScsh'
            - '$IFSksh'
            - '$IFSpdksh'
            - '$IFSsh'
            - '$IFStcsh'
            - '$IFSzsh'
    condition: all of selection_*
falsepositives:
    - Unlikely
level: high

title: Shell Execution via Find - Linux
id: 6adfbf8f-52be-4444-9bac-81b539624146
status: test
description: |
    Detects the use of the find command to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or exploitation attempt.
references:
    - https://gtfobins.github.io/gtfobins/find/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith: '/find'
        CommandLine|contains|all:
            - ' . '
            - '-exec'
    selection_cli:
        CommandLine|contains:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

title: Potential GobRAT File Discovery Via Grep
id: e34cfa0c-0a50-4210-9cb3-5632d08eb041
status: test
description: Detects the use of grep to discover specific files created by the GobRAT malware
references:
    - https://blogs.jpcert.or.jp/en/2023/05/gobrat.html
    - https://www.virustotal.com/gui/file/60bcd645450e4c846238cf0e7226dc40c84c96eba99f6b2cffcd0ab4a391c8b3/detection
    - https://www.virustotal.com/gui/file/3e44c807a25a56f4068b5b8186eee5002eed6f26d665a8b791c472ad154585d1/detection
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2023-06-02
tags:
    - attack.discovery
    - attack.t1082
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/grep'
        CommandLine|contains:
            - 'apached'
            - 'frpc'
            - 'sshd.sh'
            - 'zone.arm'
    condition: selection
falsepositives:
    - Unknown
level: high

title: Triple Cross eBPF Rootkit Install Commands
id: 22236d75-d5a0-4287-bf06-c93b1770860f
status: test
description: Detects default install commands of the Triple Cross eBPF rootkit based on the "deployer.sh" script
references:
    - https://github.com/h3xduck/TripleCross/blob/1f1c3e0958af8ad9f6ebe10ab442e75de33e91de/apps/deployer.sh
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-05
tags:
    - attack.stealth
    - attack.t1014
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/sudo'
        CommandLine|contains|all:
            - ' tc '
            - ' enp0s3 '
        CommandLine|contains:
            - ' qdisc '
            - ' filter '
    condition: selection
falsepositives:
    - Unlikely
level: high

title: OMIGOD SCX RunAsProvider ExecuteShellCommand
id: 21541900-27a9-4454-9c4c-3f0a4240344a
status: test
description: |
    Rule to detect the use of the SCX RunAsProvider Invoke_ExecuteShellCommand to execute any UNIX/Linux command using the /bin/sh shell.
    SCXcore, started as the Microsoft Operations Manager UNIX/Linux Agent, is now used in a host of products including
    Microsoft Operations Manager, Microsoft Azure, and Microsoft Operations Management Suite.
references:
    - https://www.wiz.io/blog/omigod-critical-vulnerabilities-in-omi-azure
    - https://github.com/Azure/Azure-Sentinel/pull/3059
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), MSTIC
date: 2021-10-15
modified: 2022-10-05
tags:
    - attack.privilege-escalation
    - attack.initial-access
    - attack.execution
    - attack.t1068
    - attack.t1190
    - attack.t1203
logsource:
    product: linux
    category: process_creation
detection:
    selection:
        User: root
        LogonId: 0
        CurrentDirectory: '/var/opt/microsoft/scx/tmp'
        CommandLine|contains: '/bin/sh'
    condition: selection
falsepositives:
    - Legitimate use of SCX RunAsProvider Invoke_ExecuteShellCommand.
level: high

title: Suspicious Download and Execute Pattern via Curl/Wget
id: a2d9e2f3-0f43-4c7a-bcd9-9acfc0d723aa
status: experimental
description: |
    Detects suspicious use of command-line tools such as curl or wget to download remote
    content - particularly scripts - into temporary directories (e.g., /dev/shm, /tmp), followed by
    immediate execution, indicating potential malicious activity. This pattern is commonly used
    by malicious scripts, stagers, or downloaders in fileless or multi-stage Linux attacks.
references:
    - https://gtfobins.github.io/gtfobins/wget/
    - https://gtfobins.github.io/gtfobins/curl/
author: Aayush Gupta
date: 2025-06-17
tags:
    - attack.execution
    - attack.t1059.004
    - attack.t1203
logsource:
    category: process_creation
    product: linux
detection:
    selection_downloader:
        CommandLine|contains:
            - '/curl'
            - '/wget'
    selection_tmp:
        CommandLine|contains:
            - '/tmp/'
            - '/dev/shm/'
    selection_executor:
        CommandLine|contains: 'sh -c'
    condition: all of selection_*
falsepositives:
    - System update scripts using temporary files
    - Installer scripts or automated provisioning tools
level: high

title: Shell Execution via Flock - Linux
id: 4b09c71e-4269-4111-9cdd-107d8867f0cc
status: test
description: |
    Detects the use of the "flock" command to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/flock/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith: '/flock'
        CommandLine|contains: ' -u '
    selection_cli:
        CommandLine|contains:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

title: Suspicious Invocation of Shell via AWK - Linux
id: 8c1a5675-cb85-452f-a298-b01b22a51856
status: test
description: |
    Detects the execution of "awk" or it's sibling commands, to invoke a shell using the system() function.
    This behavior is commonly associated with attempts to execute arbitrary commands or escalate privileges, potentially leading to unauthorized access or further exploitation.
references:
    - https://gtfobins.github.io/gtfobins/awk/#shell
    - https://gtfobins.github.io/gtfobins/gawk/#shell
    - https://gtfobins.github.io/gtfobins/nawk/#shell
    - https://gtfobins.github.io/gtfobins/mawk/#shell
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith:
            - '/awk'
            - '/gawk'
            - '/mawk'
            - '/nawk'
        CommandLine|contains: 'BEGIN {system'
    selection_cli:
        CommandLine|contains:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

title: Python One-Liners with Base64 Decoding - Linux
id: 55e862a8-dd9c-4651-807a-f21fcad56716
related:
    - id: 50a0aa3d-ab16-4594-a8aa-5145a6e6792b
      type: similar
status: experimental
description: |
    Detects the use of Python's base64 decoding functions in command line executions on Linux systems.
    Malicious scripts often use python one-liners to decode and execute base64-encoded payloads, which is a common technique for obfuscation and evasion.
references:
    - https://docs.python.org/3/library/base64.html
    - https://www.virustotal.com/gui/file/bc43e925d7b4b74319f6e74e836a96f1997ba404e14ac566cf12a21e9da463db/behavior
    - https://cloud.google.com/blog/topics/threat-intelligence/cybercriminals-weaponize-fake-ai-websites
author: Hugh Ryan (HueCodes), Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2026-03-09
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059.006
    - attack.t1027.010
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|contains: '/python'
    selection_cli:
        CommandLine|contains|all:
            - 'import'
            - 'base64'
            - ' -c'
        CommandLine|contains:
            - '.decode'
            - 'b16decode'
            - 'b32decode'
            - 'b32hexdecode'
            - 'b64decode'
            - 'b85decode'
            - 'z85decode'
    condition: all of selection_*
falsepositives:
    - Legitimate use of Python for decoding data, which is uncommon in typical enterprise environments but possible in development or data analysis contexts.
level: high

title: Script Interpreter Spawning Credential Scanner - Linux
id: f0025a69-e1b7-4dda-a53c-db21fa2d4071
related:
    - id: 0f60b28c-64dd-4e2c-9a63-5334d3e3a6e6
      type: similar
status: experimental
description: |
    Detects a script interpreter process (like node.js or bun) spawning a known credential scanning tool (e.g., trufflehog, gitleaks).
    This behavior is indicative of an attempt to find and steal secrets, as seen in the "Shai-Hulud: The Second Coming" campaign.
references:
    - https://github.com/asyncapi/cli/blob/2efa4dff59bc3d3cecdf897ccf178f99b115d63d/bun_environment.js
    - https://www.stepsecurity.io/blog/sha1-hulud-the-second-coming-zapier-ens-domains-and-other-prominent-npm-packages-compromised
    - https://www.endorlabs.com/learn/shai-hulud-2-malware-campaign-targets-github-and-cloud-credentials-using-bun-runtime
    - https://semgrep.dev/blog/2025/digging-for-secrets-sha1-hulud-the-second-coming-of-the-npm-worm/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-11-25
tags:
    - attack.credential-access
    - attack.t1552
    - attack.execution
    - attack.collection
    - attack.t1005
    - attack.t1059.004
logsource:
    category: process_creation
    product: linux
detection:
    selection_parent:
        ParentImage|endswith:
         # Add more script interpreters as needed
            - '/node'
            - '/bun'
    selection_child:
        - Image|endswith:
              - '/trufflehog'
              - '/gitleaks'
        - CommandLine|contains:
              - 'trufflehog'
              - 'gitleaks'
    condition: all of selection_*
falsepositives:
    - Legitimate pre-commit hooks or CI/CD pipeline jobs that use a script to run a credential scanner as part of a security check.
level: high

title: Shell Execution via Nice - Linux
id: 093d68c7-762a-42f4-9f46-95e79142571a
status: test
description: |
    Detects the use of the "nice" utility to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/nice/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/nice'
        CommandLine|endswith:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: selection
falsepositives:
    - Unknown
level: high

title: Suspicious Java Children Processes
id: d292e0af-9a18-420c-9525-ec0ac3936892
status: test
description: Detects java process spawning suspicious children
references:
    - https://www.tecmint.com/different-types-of-linux-shells/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-06-03
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        ParentImage|endswith: '/java'
        CommandLine|contains:
            - '/bin/sh'
            - 'bash'
            - 'dash'
            - 'ksh'
            - 'zsh'
            - 'csh'
            - 'fish'
            - 'curl'
            - 'wget'
            - 'python'
    condition: selection
falsepositives:
    - Unknown
level: high

title: Vim GTFOBin Abuse - Linux
id: 7ab8f73a-fcff-428b-84aa-6a5ff7877dea
status: test
description: |
    Detects the use of "vim" and it's siblings commands to execute a shell or proxy commands.
    Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/vim/
    - https://gtfobins.github.io/gtfobins/rvim/
    - https://gtfobins.github.io/gtfobins/vimdiff/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-12-28
modified: 2024-09-02
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith:
            - '/rvim'
            - '/vim'
            - '/vimdiff'
        CommandLine|contains:
            - ' --cmd'
            - ' -c '
    selection_cli:
        CommandLine|contains:
            - ':!/'
            - ':lua '
            - ':py '
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

title: Shell Invocation Via Ssh - Linux
id: 8737b7f6-8df3-4bb7-b1da-06019b99b687
status: test
description: |
    Detects the use of the "ssh" utility to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/ssh/
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-08-29
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith: '/ssh'
        CommandLine|contains:
            - 'ProxyCommand=;'
            - 'permitlocalcommand=yes'
            - 'localhost'
    selection_cli:
        CommandLine|contains:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
            - 'sh 0<&2 1>&2'
            - 'sh 1>&2 0<&2'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

title: OMIGOD SCX RunAsProvider ExecuteScript
id: 6eea1bf6-f8d2-488a-a742-e6ef6c1b67db
status: test
description: |
    Rule to detect the use of the SCX RunAsProvider ExecuteScript to execute any UNIX/Linux script using the /bin/sh shell.
    Script being executed gets created as a temp file in /tmp folder with a scx* prefix.
    Then it is invoked from the following directory /etc/opt/microsoft/scx/conf/tmpdir/.
    The file in that directory has the same prefix scx*. SCXcore, started as the Microsoft Operations Manager UNIX/Linux Agent, is now used in a host of products including
    Microsoft Operations Manager, Microsoft Azure, and Microsoft Operations Management Suite.
references:
    - https://www.wiz.io/blog/omigod-critical-vulnerabilities-in-omi-azure
    - https://github.com/Azure/Azure-Sentinel/pull/3059
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), MSTIC
date: 2021-10-15
modified: 2022-10-05
tags:
    - attack.privilege-escalation
    - attack.initial-access
    - attack.execution
    - attack.t1068
    - attack.t1190
    - attack.t1203
logsource:
    product: linux
    category: process_creation
detection:
    selection:
        User: root
        LogonId: 0
        CurrentDirectory: '/var/opt/microsoft/scx/tmp'
        CommandLine|contains: '/etc/opt/microsoft/scx/conf/tmpdir/scx'
    condition: selection
falsepositives:
    - Legitimate use of SCX RunAsProvider ExecuteScript.
level: high

title: Shell Invocation via Env Command - Linux
id: bed978f8-7f3a-432b-82c5-9286a9b3031a
status: test
description: |
    Detects the use of the env command to invoke a shell. This may indicate an attempt to bypass restricted environments, escalate privileges, or execute arbitrary commands.
references:
    - https://gtfobins.github.io/gtfobins/env/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
modified: 2026-01-08
tags:
    - attack.execution
    - attack.t1059.004
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/env'
        CommandLine|contains:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: selection
falsepositives:
    - Github operations such as ghe-backup
level: high

title: Linux Webshell Indicators
id: 818f7b24-0fba-4c49-a073-8b755573b9c7
status: test
description: Detects suspicious sub processes of web server processes
references:
    - https://www.acunetix.com/blog/articles/web-shells-101-using-php-introduction-web-shells-part-2/
    - https://media.defense.gov/2020/Jun/09/2002313081/-1/-1/0/CSI-DETECT-AND-PREVENT-WEB-SHELL-MALWARE-20200422.PDF
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2021-10-15
modified: 2022-12-28
tags:
    - attack.persistence
    - attack.t1505.003
logsource:
    product: linux
    category: process_creation
detection:
    selection_general:
        ParentImage|endswith:
            - '/httpd'
            - '/lighttpd'
            - '/nginx'
            - '/apache2'
            - '/node'
            - '/caddy'
    selection_tomcat:
        ParentCommandLine|contains|all:
            - '/bin/java'
            - 'tomcat'
    selection_websphere:  # ? just guessing
        ParentCommandLine|contains|all:
            - '/bin/java'
            - 'websphere'
    sub_processes:
        Image|endswith:
            - '/whoami'
            - '/ifconfig'
            - '/ip'
            - '/bin/uname'
            - '/bin/cat'
            - '/bin/crontab'
            - '/hostname'
            - '/iptables'
            - '/netstat'
            - '/pwd'
            - '/route'
    condition: 1 of selection_* and sub_processes
falsepositives:
    - Web applications that invoke Linux command line tools
level: high

title: Linux HackTool Execution
id: a015e032-146d-4717-8944-7a1884122111
status: test
description: Detects known hacktool execution based on image name.
references:
    - https://github.com/Gui774ume/ebpfkit
    - https://github.com/pathtofile/bad-bpf
    - https://github.com/carlospolop/PEASS-ng
    - https://github.com/t3l3machus/hoaxshell
    - https://github.com/t3l3machus/Villain
    - https://github.com/HavocFramework/Havoc
    - https://github.com/1N3/Sn1per
    - https://github.com/Ne0nd0g/merlin
    - https://github.com/Pennyw0rth/NetExec/
author: Nasreddine Bencherchali (Nextron Systems), Georg Lauenstein (sure[secure])
date: 2023-01-03
modified: 2024-09-19
tags:
    - attack.execution
    - attack.resource-development
    - attack.t1587
logsource:
    product: linux
    category: process_creation
detection:
    selection_c2_frameworks:
        Image|endswith:
            - '/crackmapexec'
            - '/havoc'
            - '/merlin-agent'
            - '/merlinServer-Linux-x64'
            - '/msfconsole'
            - '/msfvenom'
            - '/ps-empire server'
            - '/ps-empire'
            - '/sliver-client'
            - '/sliver-server'
            - '/Villain.py'
    selection_c2_framework_cobaltstrike:
        Image|contains:
            - '/cobaltstrike'
            - '/teamserver'
    selection_scanners:
        Image|endswith:
            - '/autorecon'
            - '/httpx'
            - '/legion'
            - '/naabu'
            - '/netdiscover'
            - '/nuclei'
            - '/recon-ng'
    selection_scanners_sniper:
        Image|contains: '/sniper'
    selection_web_enum:
        Image|endswith:
            - '/dirb'
            - '/dirbuster'
            - '/eyewitness'
            - '/feroxbuster'
            - '/ffuf'
            - '/gobuster'
            - '/wfuzz'
            - '/whatweb'
    selection_web_vuln:
        Image|endswith:
            - '/joomscan'
            - '/nikto'
            - '/wpscan'
    selection_exploit_tools:
        Image|endswith:
            - '/aircrack-ng'
            - '/bloodhound-python'
            - '/bpfdos'
            - '/ebpfki'
            - '/evil-winrm'
            - '/hashcat'
            - '/hoaxshell.py'
            - '/hydra'
            - '/john'
            - '/ncrack'
            # default binary: https://github.com/Pennyw0rth/NetExec/releases/download/v1.0.0/nxc-ubuntu-latest
            - '/nxc-ubuntu-latest'
            - '/pidhide'
            - '/pspy32'
            - '/pspy32s'
            - '/pspy64'
            - '/pspy64s'
            - '/setoolkit'
            - '/sqlmap'
            - '/writeblocker'
    selection_linpeas:
        # covers: all linux versions listed here: https://github.com/carlospolop/PEASS-ng/releases
        Image|contains: '/linpeas'
    condition: 1 of selection_*
falsepositives:
    - Unlikely
level: high

title: Linux Keylogging with Pam.d
id: 49aae26c-450e-448b-911d-b3c13d178dfc
status: test
description: Detect attempt to enable auditing of TTY input
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1056.001/T1056.001.md
    - https://linux.die.net/man/8/pam_tty_audit
    - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sec-configuring_pam_for_auditing
    - https://access.redhat.com/articles/4409591#audit-record-types-2
author: 'Pawel Mazur'
date: 2021-05-24
modified: 2022-12-18
tags:
    - attack.collection
    - attack.credential-access
    - attack.t1003
    - attack.t1056.001
logsource:
    product: linux
    service: auditd
detection:
    selection_path_events:
        type: PATH
        name:
            - '/etc/pam.d/system-auth'
            - '/etc/pam.d/password-auth'
    selection_tty_events:
        type:
            - 'TTY'
            - 'USER_TTY'
    condition: 1 of selection_*
falsepositives:
    - Administrative work
level: high

title: BPFDoor Abnormal Process ID or Lock File Accessed
id: 808146b2-9332-4d78-9416-d7e47012d83d
status: test
description: detects BPFDoor .lock and .pid files access in temporary file storage facility
references:
    - https://www.sandflysecurity.com/blog/bpfdoor-an-evasive-linux-backdoor-technical-analysis/
    - https://www.elastic.co/security-labs/a-peek-behind-the-bpfdoor
    - https://www.rapid7.com/blog/post/tr-bpfdoor-telecom-networks-sleeper-cells-threat-research-report/
    - https://github.com/rapid7/Rapid7-Labs/blob/741c7196ec12a0a56b63463d1fd726ff14d3a97a/BPFDoor/rapid7_detect_bpfdoor.sh
author: Rafal Piasecki
date: 2022-08-10
modified: 2026-03-30
tags:
    - attack.execution
    - attack.t1106
    - attack.t1059
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: 'PATH'
        name:
            - /var/run/aepmonend.pid
            - /var/run/auditd.lock
            - /var/run/cma.lock
            - /var/run/console-kit.pid
            - /var/run/consolekit.pid
            - /var/run/daemon.pid
            - /var/run/hald-addon.pid
            - /var/run/hald-smartd.pid
            - /var/run/haldrund.pid
            - /var/run/hp-health.pid
            - /var/run/hpasmlit.lock
            - /var/run/hpasmlited.pid
            - /var/run/kdevrund.pid
            - /var/run/lldpad.lock
            - /var/run/mcelog.pid
            - /var/run/system.pid
            - /var/run/uvp-srv.pid
            - /var/run/vmtoolagt.pid
            - /var/run/xinetd.lock
    condition: selection
falsepositives:
    - Unlikely
level: high

title: Modification of ld.so.preload
id: 4b3cb710-5e83-4715-8c45-8b2b5b3e5751
status: test
description: Identifies modification of ld.so.preload for shared object injection. This technique is used by attackers to load arbitrary code into processes.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1574.006/T1574.006.md
    - https://eqllib.readthedocs.io/en/latest/analytics/fd9b987a-1101-4ed3-bda6-a70300eaf57e.html
author: E.M. Anhaus (originally from Atomic Blue Detections, Tony Lambert), oscd.community
date: 2019-10-24
modified: 2021-11-27
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.execution
    - attack.stealth
    - attack.t1574.006
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: 'PATH'
        name: '/etc/ld.so.preload'
    condition: selection
falsepositives:
    - Unknown
level: high

title: Binary Padding - Linux
id: c52a914f-3d8b-4b2a-bb75-b3991e75f8ba
status: test
description: |
    Adversaries may use binary padding to add junk data and change the on-disk representation of malware.
    This rule detect using dd and truncate to add a junk data to file.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1027.001/T1027.001.md
author: Igor Fits, oscd.community
date: 2020-10-13
modified: 2023-05-03
tags:
    - attack.stealth
    - attack.t1027.001
logsource:
    product: linux
    service: auditd
detection:
    selection_execve:
        type: 'EXECVE'
    keywords_truncate:
        '|all':
            - 'truncate'
            - '-s'
    keywords_dd:
        '|all':
            - 'dd'
            - 'if='
    keywords_filter:
        - 'of='
    condition: selection_execve and (keywords_truncate or (keywords_dd and not keywords_filter))
falsepositives:
    - Unknown
level: high
simulation:
    - type: atomic-red-team
      name: Pad Binary to Change Hash - Linux/macOS dd
      technique: T1027.001
      atomic_guid: ffe2346c-abd5-4b45-a713-bf5f1ebd573a

title: Privileged User Has Been Created
id: 0ac15ec3-d24f-4246-aa2a-3077bb1cf90e
status: test
description: Detects the addition of a new user to a privileged group such as "root" or "sudo"
references:
    - https://digital.nhs.uk/cyber-alerts/2018/cc-2825
    - https://linux.die.net/man/8/useradd
    - https://github.com/redcanaryco/atomic-red-team/blob/25acadc0b43a07125a8a5b599b28bbc1a91ffb06/atomics/T1136.001/T1136.001.md#atomic-test-5---create-a-new-user-in-linux-with-root-uid-and-gid
author: Pawel Mazur
date: 2022-12-21
modified: 2025-01-21
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1136.001
    - attack.t1098
logsource:
    product: linux
    definition: '/var/log/secure on REHL systems or /var/log/auth.log on debian like Systems needs to be collected in order for this detection to work'
detection:
    # Example of the events that could be observed when matching these would be as follow
    #   Dec 21 16:42:19 testserver useradd[1337]: new user: name=butter1, UID=1000, GID=0, home=/root, shell=/bin/bash
    #   Dec 21 17:13:54 testserver useradd[1337]: new user: name=john, UID=0, GID=0, home=/home/john, shell=/bin/bash
    #   Dec 21 17:24:40 testserver useradd[1337]: new user: name=butter3, UID=1000, GID=10, home=/home/butter3, shell=/bin/bash
    #   Dec 21 17:30:22 testserver useradd[1337]: new user: name=butter4, UID=1000, GID=27, home=/home/butter4, shell=/bin/bash
    selection_new_user:
        - 'new user'
    selection_uids_gids:
        - 'GID=0,' # root group
        - 'UID=0,' # root UID
        - 'GID=10,' # wheel group
        - 'GID=27,' # sudo group
    condition: all of selection_*
falsepositives:
    - Administrative activity
level: high

title: Buffer Overflow Attempts
id: 18b042f0-2ecd-4b6e-9f8d-aa7a7e7de781
status: test
description: Detects buffer overflow attempts in Unix system log files
references:
    - https://github.com/ossec/ossec-hids/blob/1ecffb1b884607cb12e619f9ab3c04f530801083/etc/rules/attack_rules.xml  # OSSEC attack detection rules​:contentReference[oaicite:6]{index=6}​:contentReference[oaicite:7]{index=7}
    - https://docs.oracle.com/cd/E19683-01/816-4883/6mb2joatd/index.html  # Exec stack syslog message (noexec_user_stack)​:contentReference[oaicite:8]{index=8}
    - https://www.giac.org/paper/gcih/266/review-ftp-protocol-cyber-defense-initiative/102802  # WU-FTPD exploit "0bin0sh" analysis​:contentReference[oaicite:9]{index=9}
    - https://blu.org/mhonarc/discuss/2001/04/msg00285.php  # RPC.statd exploit attempt log example​:contentReference[oaicite:10]{index=10}
    - https://rapid7.com/blog/post/2019/02/19/stack-based-buffer-overflow-attacks-what-you-need-to-know/  # Stack smashing protector alert example​:contentReference[oaicite:11]{index=11}
author: Florian Roth (Nextron Systems)
date: 2017-03-01
modified: 2025-03-17
tags:
    - attack.t1068
    - attack.privilege-escalation
logsource:
    product: linux
detection:
    keywords:
        - 'attempt to execute code on stack by'
        - '0bin0sh1'
        # - 'rpc.statd[\d+]: gethostbyname error for'  # it's an expensive regex and produces questionable results
        - 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'  # this can cause false positives in Base64 encoded data
        - 'stack smashing detected'
    condition: keywords
falsepositives:
    - Base64 encoded data in log entries
level: high

title: Symlink Etc Passwd
id: c67fc22a-0be5-4b4f-aad5-2b32c4b69523
status: test
description: Detects suspicious command lines that look as if they would create symbolic links to /etc/passwd
references:
    - https://www.qualys.com/2021/05/04/21nails/21nails.txt
author: Florian Roth (Nextron Systems)
date: 2019-04-05
modified: 2021-11-27
tags:
    - attack.t1204.001
    - attack.execution
logsource:
    product: linux
detection:
    keywords:
        - 'ln -s -f /etc/passwd'
        - 'ln -s /etc/passwd'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: JexBoss Command Sequence
id: 8ec2c8b4-557a-4121-b87c-5dfb3a602fae
status: test
description: Detects suspicious command sequence that JexBoss
references:
    - https://www.us-cert.gov/ncas/analysis-reports/AR18-312A
author: Florian Roth (Nextron Systems)
date: 2017-08-24
modified: 2025-11-22
tags:
    - attack.execution
    - attack.t1059.004
logsource:
    product: linux
detection:
    keywords:
        '|all':
            - 'bash -c /bin/bash'
            - '&/dev/tcp/'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: Suspicious Reverse Shell Command Line
id: 738d9bcf-6999-4fdb-b4ac-3033037db8ab
status: test
description: Detects suspicious shell commands or program code that may be executed or used in command line to establish a reverse shell
references:
    - https://alamot.github.io/reverse_shells/
author: Florian Roth (Nextron Systems)
date: 2019-04-02
modified: 2021-11-27
tags:
    - attack.execution
    - attack.t1059.004
logsource:
    product: linux
detection:
    keywords:
        - 'BEGIN {s = "/inet/tcp/0/'
        - 'bash -i >& /dev/tcp/'
        - 'bash -i >& /dev/udp/'
        - 'sh -i >$ /dev/udp/'
        - 'sh -i >$ /dev/tcp/'
        - '&& while read line 0<&5; do'
        - '/bin/bash -c exec 5<>/dev/tcp/'
        - '/bin/bash -c exec 5<>/dev/udp/'
        - 'nc -e /bin/sh '
        - '/bin/sh | nc'
        - 'rm -f backpipe; mknod /tmp/backpipe p && nc '
        - ';socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i))))'
        - ';STDIN->fdopen($c,r);$~->fdopen($c,w);system$_ while<>;'
        - '/bin/sh -i <&3 >&3 2>&3'
        - 'uname -a; w; id; /bin/bash -i'
        - '$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2); $stream.Write($sendbyte,0,$sendbyte.Length); $stream.Flush()};'
        - ';os.dup2(s.fileno(),0);os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);os.putenv(''HISTFILE'',''/dev/null'');'
        - '.to_i;exec sprintf("/bin/sh -i <&%d >&%d 2>&%d",f,f,f)'
        - ';while(cmd=c.gets);IO.popen(cmd,"r"){|io|c.print'
        - 'socat exec:''bash -li'',pty,stderr,setsid,sigint,sane tcp:'
        - 'rm -f /tmp/p; mknod /tmp/p p &&'
        - ' | /bin/bash | telnet '
        - ',echo=0,raw tcp-listen:'
        - 'nc -lvvp '
        - 'xterm -display 1'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: Shellshock Expression
id: c67e0c98-4d39-46ee-8f6b-437ebf6b950e
status: test
description: Detects shellshock expressions in log files
references:
    - https://owasp.org/www-pdf-archive/Shellshock_-_Tudor_Enache.pdf
author: Florian Roth (Nextron Systems)
date: 2017-03-14
modified: 2022-10-09
tags:
    - attack.persistence
    - attack.t1505.003
logsource:
    product: linux
detection:
    keywords:
        - '(){:;};'
        - '() {:;};'
        - '() { :;};'
        - '() { :; };'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: Equation Group Indicators
id: 41e5c73d-9983-4b69-bd03-e13b67e9623c
status: test
description: Detects suspicious shell commands used in various Equation Group scripts and tools
references:
    - https://medium.com/@shadowbrokerss/dont-forget-your-base-867d304a94b1
author: Florian Roth (Nextron Systems)
date: 2017-04-09
modified: 2021-11-27
tags:
    - attack.execution
    - attack.g0020
    - attack.t1059.004
logsource:
    product: linux
detection:
    keywords:
        # evolvingstrategy, elgingamble, estesfox
        - 'chown root*chmod 4777 '
        - 'cp /bin/sh .;chown'
        # tmpwatch
        - 'chmod 4777 /tmp/.scsi/dev/bin/gsh'
        - 'chown root:root /tmp/.scsi/dev/bin/'
        # estesfox
        - 'chown root:root x;'
        # ratload
        - '/bin/telnet locip locport < /dev/console | /bin/sh'
        - '/tmp/ratload'
        # ewok
        - 'ewok -t '
        # xspy
        - 'xspy -display '
        # elatedmonkey
        - 'cat > /dev/tcp/127.0.0.1/80 <<END'
        # ftshell
        - 'rm -f /current/tmp/ftshell.latest'
        # ghost
        - 'ghost_* -v '
        # morerats client
        - ' --wipe > /dev/null'
        # noclient
        - 'ping -c 2 *; grep * /proc/net/arp >/tmp/gx'
        - 'iptables * OUTPUT -p tcp -d 127.0.0.1 --tcp-flags RST RST -j DROP;'
        # auditcleaner
        - '> /var/log/audit/audit.log; rm -f .'
        - 'cp /var/log/audit/audit.log .tmp'
        # reverse shell
        - 'sh >/dev/tcp/* <&1 2>&1'
        # packrat
        - 'ncat -vv -l -p * <'
        - 'nc -vv -l -p * <'
        # empty bowl
        - '< /dev/console | uudecode && uncompress'
        - 'sendmail -osendmail;chmod +x sendmail'
        # echowrecker
        - '/usr/bin/wget -O /tmp/a http* && chmod 755 /tmp/cron'
        # dubmoat
        - 'chmod 666 /var/run/utmp~'
        # poptop
        - 'chmod 700 nscd crond'
        # abopscript
        - 'cp /etc/shadow /tmp/.'
        # ys
        - '</dev/console |uudecode > /dev/null 2>&1 && uncompress'
        # jacktelnet
        - 'chmod 700 jp&&netstat -an|grep'
        # others
        - 'uudecode > /dev/null 2>&1 && uncompress -f * && chmod 755'
        - 'chmod 700 crond'
        - 'wget http*; chmod +x /tmp/sendmail'
        - 'chmod 700 fp sendmail pt'
        - 'chmod 755 /usr/vmsys/bin/pipe'
        - 'chmod -R 755 /usr/vmsys'
        - 'chmod 755 $opbin/*tunnel'
        - 'chmod 700 sendmail'
        - 'chmod 0700 sendmail'
        - '/usr/bin/wget http*sendmail;chmod +x sendmail;'
        - '&& telnet * 2>&1 </dev/console'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: Suspicious Activity in Shell Commands
id: 2aa1440c-9ae9-4d92-84a7-a9e5f5e31695
status: test
description: Detects suspicious shell commands used in various exploit codes (see references)
references:
    - https://web.archive.org/web/20170319121015/http://www.threatgeek.com/2017/03/widespread-exploitation-attempts-using-cve-2017-5638.html
    - https://github.com/rapid7/metasploit-framework/blob/eb6535009f5fdafa954525687f09294918b5398d/modules/exploits/multi/http/struts_code_exec_exception_delegator.rb
    - http://pastebin.com/FtygZ1cg
    - https://artkond.com/2017/03/23/pivoting-guide/
author: Florian Roth (Nextron Systems)
date: 2017-08-21
modified: 2021-11-27
tags:
    - attack.execution
    - attack.t1059.004
logsource:
    product: linux
detection:
    keywords:
        # Generic suspicious commands
        - 'wget * - http* | perl'
        - 'wget * - http* | sh'
        - 'wget * - http* | bash'
        - 'python -m SimpleHTTPServer'
        - '-m http.server'      # Python 3
        - 'import pty; pty.spawn*'
        - 'socat exec:*'
        - 'socat -O /tmp/*'
        - 'socat tcp-connect*'
        - '*echo binary >>*'
        # Malware
        - '*wget *; chmod +x*'
        - '*wget *; chmod 777 *'
        - '*cd /tmp || cd /var/run || cd /mnt*'
        # Apache Struts in-the-wild exploit codes
        - '*stop;service iptables stop;*'
        - '*stop;SuSEfirewall2 stop;*'
        - 'chmod 777 2020*'
        - '*>>/etc/rc.local'
        # Metasploit framework exploit codes
        - '*base64 -d /tmp/*'
        - '* | base64 -d *'
        - '*/chmod u+s *'
        - '*chmod +s /tmp/*'
        - '*chmod u+s /tmp/*'
        - '* /tmp/haxhax*'
        - '* /tmp/ns_sploit*'
        - 'nc -l -p *'
        - 'cp /bin/ksh *'
        - 'cp /bin/sh *'
        - '* /tmp/*.b64 *'
        - '*/tmp/ysocereal.jar*'
        - '*/tmp/x *'
        - '*; chmod +x /tmp/*'
        - '*;chmod +x /tmp/*'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: Code Injection by ld.so Preload
id: 7e3c4651-c347-40c4-b1d4-d48590fdf684
status: test
description: Detects the ld.so preload persistence file. See `man ld.so` for more information.
references:
    - https://man7.org/linux/man-pages/man8/ld.so.8.html
author: Christian Burkard (Nextron Systems)
date: 2021-05-05
modified: 2022-10-09
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.006
logsource:
    product: linux
detection:
    keywords:
        - '/etc/ld.so.preload'
    condition: keywords
falsepositives:
    - Rare temporary workaround for library misconfiguration
level: high

title: Suspicious Named Error
id: c8e35e96-19ce-4f16-aeb6-fd5588dc5365
status: test
description: Detects suspicious DNS error messages that indicate a fatal or suspicious error that could be caused by exploiting attempts
references:
    - https://github.com/ossec/ossec-hids/blob/1ecffb1b884607cb12e619f9ab3c04f530801083/etc/rules/named_rules.xml
author: Florian Roth (Nextron Systems)
date: 2018-02-20
modified: 2022-10-05
tags:
    - attack.initial-access
    - attack.t1190
logsource:
    product: linux
    service: syslog
detection:
    keywords:
        - ' dropping source port zero packet from '
        - ' denied AXFR from '
        - ' exiting (due to fatal error)'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: Relevant ClamAV Message
id: 36aa86ca-fd9d-4456-814e-d3b1b8e1e0bb
status: stable
description: Detects relevant ClamAV messages
references:
    - https://github.com/ossec/ossec-hids/blob/1ecffb1b884607cb12e619f9ab3c04f530801083/etc/rules/clam_av_rules.xml
author: Florian Roth (Nextron Systems)
date: 2017-03-01
tags:
    - attack.resource-development
    - attack.t1588.001
logsource:
    product: linux
    service: clamav
detection:
    keywords:
        - 'Trojan*FOUND'
        - 'VirTool*FOUND'
        - 'Webshell*FOUND'
        - 'Rootkit*FOUND'
        - 'Htran*FOUND'
    condition: keywords
falsepositives:
    - Unknown
level: high

title: Suspicious Filename with Embedded Base64 Commands
id: 179b3686-6271-4d87-807d-17d843a8af73
status: experimental
description: |
    Detects files with specially crafted filenames that embed Base64-encoded bash payloads designed to execute when processed by shell scripts.
    These filenames exploit shell interpretation quirks to trigger hidden commands, a technique observed in VShell malware campaigns.
references:
    - https://www.trellix.com/blogs/research/the-silent-fileless-threat-of-vshell/
author: '@kostastsale'
date: 2025-11-22
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059.004
    - attack.t1027
logsource:
    product: linux
    category: file_event
detection:
    selection:
        TargetFilename|contains:
            - '{echo'
            - '{base64,-d}'
    condition: selection
falsepositives:
    - Legitimate files with similar naming patterns (very unlikely).
level: high

title: Triple Cross eBPF Rootkit Default Persistence
id: 1a2ea919-d11d-4d1e-8535-06cda13be20f
status: test
description: Detects the creation of "ebpfbackdoor" files in both "cron.d" and "sudoers.d" directories. Which both are related to the TripleCross persistence method
references:
    - https://github.com/h3xduck/TripleCross/blob/12629558b8b0a27a5488a0b98f1ea7042e76f8ab/apps/deployer.sh
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-05
modified: 2022-12-31
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.persistence
    - attack.t1053.003
logsource:
    product: linux
    category: file_event
detection:
    selection:
        TargetFilename|endswith: 'ebpfbackdoor'
    condition: selection
falsepositives:
    - Unlikely
level: high

title: Possible Impacket SecretDump Remote Activity - Zeek
id: 92dae1ed-1c9d-4eff-a567-33acbd95b00e
status: test
description: 'Detect AD credential dumping using impacket secretdump HKTL. Based on the SIGMA rules/windows/builtin/win_impacket_secretdump.yml'
references:
    - https://web.archive.org/web/20230329153811/https://blog.menasec.net/2019/02/threat-huting-10-impacketsecretdump.html
author: 'Samir Bousseaden, @neu5ron'
date: 2020-03-19
modified: 2021-11-27
tags:
    - attack.credential-access
    - attack.t1003.002
    - attack.t1003.004
    - attack.t1003.003
logsource:
    product: zeek
    service: smb_files
detection:
    selection:
        path|contains|all:
            - '\'
            - 'ADMIN$'
        name|contains: 'SYSTEM32\'
        name|endswith: '.tmp'
    condition: selection
falsepositives:
    - Unknown
level: high

title: First Time Seen Remote Named Pipe - Zeek
id: 021310d9-30a6-480a-84b7-eaa69aeb92bb
related:
    - id: 52d8b0c6-53d6-439a-9e41-52ad442ad9ad
      type: derived
status: test
description: This detection excludes known namped pipes accessible remotely and notify on newly observed ones, may help to detect lateral movement and remote exec using named pipes
references:
    - https://twitter.com/menasec1/status/1104489274387451904
author: Samir Bousseaden, @neu5ron, Tim Shelton
date: 2020-04-02
modified: 2022-12-27
tags:
    - attack.lateral-movement
    - attack.t1021.002
logsource:
    product: zeek
    service: smb_files
detection:
    selection:
        path: '\\\\\*\\IPC$' # Looking for the string \\*\IPC$
    filter_keywords:
        - 'samr'
        - 'lsarpc'
        - 'winreg'
        - 'netlogon'
        - 'srvsvc'
        - 'protected_storage'
        - 'wkssvc'
        - 'browser'
        - 'netdfs'
        - 'svcctl'
        - 'spoolss'
        - 'ntsvcs'
        - 'LSM_API_service'
        - 'HydraLsPipe'
        - 'TermSrv_API_service'
        - 'MsFteWds'
    condition: selection and not 1 of filter_*
falsepositives:
    - Update the excluded named pipe to filter out any newly observed legit named pipe
level: high

title: Suspicious PsExec Execution - Zeek
id: f1b3a22a-45e6-4004-afb5-4291f9c21166
related:
    - id: c462f537-a1e3-41a6-b5fc-b2c2cef9bf82
      type: derived
status: test
description: detects execution of psexec or paexec with renamed service name, this rule helps to filter out the noise if psexec is used for legit purposes or if attacker uses a different psexec client other than sysinternal one
references:
    - https://web.archive.org/web/20230329171218/https://blog.menasec.net/2019/02/threat-hunting-3-detecting-psexec.html
author: Samir Bousseaden, @neu5ron, Tim Shelton
date: 2020-04-02
modified: 2022-12-27
tags:
    - attack.lateral-movement
    - attack.t1021.002
logsource:
    product: zeek
    service: smb_files
detection:
    selection:
        path|contains|all:
            - '\\'
            - '\IPC$'
        name|endswith:
            - '-stdin'
            - '-stdout'
            - '-stderr'
    filter:
        name|startswith: 'PSEXESVC'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high