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: Copy Passwd Or Shadow From TMP Path
id: fa4aaed5-4fe0-498d-bbc0-08e3346387ba
status: test
description: Detects when the file "passwd" or "shadow" is copied from tmp path
references:
    - https://blogs.blackberry.com/
    - https://twitter.com/Joseliyo_Jstnk/status/1620131033474822144
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2023-01-31
tags:
    - attack.credential-access
    - attack.t1552.001
logsource:
    product: linux
    category: process_creation
detection:
    selection_img:
        Image|endswith: '/cp'
    selection_path:
        CommandLine|contains: '/tmp/'
    selection_file:
        CommandLine|contains:
            - 'passwd'
            - 'shadow'
    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: 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: Linux Recon Indicators
id: 0cf7a157-8879-41a2-8f55-388dd23746b7
status: test
description: Detects events with patterns found in commands used for reconnaissance on linux systems
references:
    - https://github.com/sleventyeleven/linuxprivchecker/blob/0d701080bbf92efd464e97d71a70f97c6f2cd658/linuxprivchecker.py
author: Florian Roth (Nextron Systems)
date: 2022-06-20
tags:
    - attack.reconnaissance
    - attack.t1592.004
    - attack.credential-access
    - attack.t1552.001
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        CommandLine|contains:
            - ' -name .htpasswd'
            - ' -perm -4000 '
    condition: selection
falsepositives:
    - Legitimate administration activities
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: Kaspersky Endpoint Security Stopped Via CommandLine - Linux
id: 36388120-b3f1-4ce9-b50b-280d9a7f4c04
status: experimental
description: |
  Detects execution of the Kaspersky init.d stop script on Linux systems either directly or via systemctl.
  This activity may indicate a manual interruption of the antivirus service by an administrator, or it could be a sign of potential tampering or evasion attempts by malicious actors.
references:
    - https://support.kaspersky.com/KES4Linux/12.0.0/en-US/197929.htm
author: Milad Cheraghi
date: 2025-10-18
tags:
    - attack.execution
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: linux
    category: process_creation
detection:
    selection:
        Image|endswith:
            # Note: Add the list of shells allowed in your environment that can be used to run init.d scripts.
            - '/systemctl'
            - '/bash'
            - '/sh'
        CommandLine|contains|all:
            - 'stop'
            - 'kesl'
    condition: selection
falsepositives:
    - System administrator manually stopping Kaspersky services
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: ASLR Disabled Via Sysctl or Direct Syscall - Linux
id: e497a24e-9345-4a62-9803-b06d7d7cb132
status: experimental
description: |
    Detects actions that disable Address Space Layout Randomization (ASLR) in Linux, including:
      - Use of the `personality` syscall with the ADDR_NO_RANDOMIZE flag (0x0040000)
      - Modification of the /proc/sys/kernel/randomize_va_space file
      - Execution of the `sysctl` command to set `kernel.randomize_va_space=0`
    Disabling ASLR is often used by attackers during exploit development or to bypass memory protection mechanisms.
    A successful use of these methods can reduce the effectiveness of ASLR and make memory corruption attacks more reliable.
references:
    - https://github.com/CheraghiMilad/bypass-Neo23x0-auditd-config/blob/f1c478a37911a5447d5ffcd580f22b167bf3df14/personality-syscall/README.md
    - https://man7.org/linux/man-pages/man2/personality.2.html
    - https://manual.cs50.io/2/personality
    - https://linux-audit.com/linux-aslr-and-kernelrandomize_va_space-setting/
author: Milad Cheraghi
date: 2025-05-26
modified: 2025-12-05
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.defense-impairment
    - attack.t1685
    - attack.t1055.009
logsource:
    product: linux
    service: auditd
detection:
    selection_syscall:
        type: 'SYSCALL'
        SYSCALL: 'personality'
        a0: 40000
    selection_sysctl:
        type: 'EXECVE'
        a0: 'sysctl'
        a1: '-w'
        a2: 'kernel.randomize_va_space=0' # 0 = disable
    condition: 1 of selection_*
falsepositives:
    - Debugging or legitimate software testing
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: Auditing Configuration Changes on Linux Host
id: 977ef627-4539-4875-adf4-ed8f780c4922
status: test
description: Detect changes in auditd configuration files
references:
    - https://github.com/Neo23x0/auditd/blob/master/audit.rules
    - Self Experience
author: Mikhail Larin, oscd.community
date: 2019-10-25
modified: 2021-11-27
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: PATH
        name:
            - /etc/audit/*
            - /etc/libaudit.conf
            - /etc/audisp/*
    condition: selection
falsepositives:
    - Legitimate administrative activity
level: high

title: Logging Configuration Changes on Linux Host
id: c830f15d-6f6e-430f-8074-6f73d6807841
status: test
description: Detect changes of syslog daemons configuration files
references:
    - self experience
author: Mikhail Larin, oscd.community
date: 2019-10-25
modified: 2021-11-27
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: 'PATH'
        name:
            - /etc/syslog.conf
            - /etc/rsyslog.conf
            - /etc/syslog-ng/syslog-ng.conf
    condition: selection
falsepositives:
    - Legitimate administrative activity
level: high

title: Credentials In Files - Linux
id: df3fcaea-2715-4214-99c5-0056ea59eb35
status: test
description: 'Detecting attempts to extract passwords with grep'
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1552.001/T1552.001.md
author: 'Igor Fits, oscd.community'
date: 2020-10-15
modified: 2023-04-30
tags:
    - attack.credential-access
    - attack.t1552.001
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: 'EXECVE'
    keywords:
        '|all':
            - 'grep'
            - 'password'
    condition: selection and keywords
falsepositives:
    - Unknown
level: high

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: 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: Guacamole Two Users Sharing Session Anomaly
id: 1edd77db-0669-4fef-9598-165bda82826d
status: test
description: Detects suspicious session with two users present
references:
    - https://research.checkpoint.com/2020/apache-guacamole-rce/
author: Florian Roth (Nextron Systems)
date: 2020-07-03
modified: 2021-11-27
tags:
    - attack.credential-access
    - attack.t1212
logsource:
    product: linux
    service: guacamole
detection:
    selection:
        - '(2 users now present)'
    condition: selection
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: 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