Sigma is the open generic signature format for SIEM systems. Each rule below converts to native syntax for Splunk, Elastic, Sentinel, and other SIEMs. Expand any rule to see its raw YAML.
Detects commonly-used chained commands and strings in the most recent 'url' value of the 'TypedPaths' key, which could be indicative of a user being targeted by the FileFix technique.
title: FileFix - Command Evidence in TypedPaths
id: 4fee3d51-8069-4a4c-a0f7-924fcaff2c70
related:
- id: 4be03877-d5b6-4520-85c9-a5911c0a656c
type: similar
status: experimental
description: |
Detects commonly-used chained commands and strings in the most recent 'url' value of the 'TypedPaths' key, which could be indicative of a user being targeted by the FileFix technique.
references:
- https://x.com/russianpanda9xx/status/1940831134759506029
- https://mrd0x.com/filefix-clickfix-alternative/
- https://www.scpx.com.au/2025/11/16/decades-old-finger-protocol-abused-in-clickfix-malware-attacks/
author: Alfie Champion (delivr.to), Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-07-05
modified: 2025-11-19
tags:
- attack.execution
- attack.t1204.004
logsource:
category: registry_set
product: windows
detection:
selection_base:
TargetObject|endswith: '\Software\Microsoft\Windows\CurrentVersion\Explorer\TypedPaths\url1'
Details|contains|all:
- '#'
- 'http'
selection_cmd:
- Details|contains:
# Add more suspicious keywords
- 'account'
- 'anti-bot'
- 'botcheck'
- 'captcha'
- 'challenge'
- 'confirmation'
- 'fraud'
- 'human'
- 'identification'
- 'identificator'
- 'identity'
- 'robot'
- 'validation'
- 'verification'
- 'verify'
- Details|contains:
- '%comspec%'
- 'bitsadmin'
- 'certutil'
- 'cmd'
- 'cscript'
- 'curl'
- 'finger'
- 'mshta'
- 'powershell'
- 'pwsh'
- 'regsvr32'
- 'rundll32'
- 'schtasks'
- 'wget'
- 'wscript'
condition: all of selection_*
falsepositives:
- Unknown
level: high
high
Suspicious ClickFix/FileFix Execution Pattern
Detects suspicious execution patterns where users are tricked into running malicious commands via clipboard manipulation, either through the Windows Run dialog (ClickFix) or File Explorer address bar (FileFix).
Attackers leverage social engineering campaigns—such as fake CAPTCHA challenges or urgent alerts—encouraging victims to paste clipboard contents, often executing mshta.exe, powershell.exe, or similar commands to infect systems.
status experimentalauthor montysecurity, Swachchhanda Shrawan Poudel (Nextron Systems)id d487ed4a-fd24-436d-a0b2-f4e95f7b2635
view Sigma YAML
title: Suspicious ClickFix/FileFix Execution Pattern
id: d487ed4a-fd24-436d-a0b2-f4e95f7b2635
related:
- id: f5fe36cf-f1ec-4c23-903d-09a3110f6bbb
type: similar
status: experimental
description: |
Detects suspicious execution patterns where users are tricked into running malicious commands via clipboard manipulation, either through the Windows Run dialog (ClickFix) or File Explorer address bar (FileFix).
Attackers leverage social engineering campaigns—such as fake CAPTCHA challenges or urgent alerts—encouraging victims to paste clipboard contents, often executing mshta.exe, powershell.exe, or similar commands to infect systems.
references:
- https://github.com/JohnHammond/recaptcha-phish
- https://www.zscaler.com/blogs/security-research/deepseek-lure-using-captchas-spread-malware
- https://www.threatdown.com/blog/clipboard-hijacker-tries-to-install-a-trojan/
- https://app.any.run/tasks/5c16b4db-4b36-4039-a0ed-9b09abff8be2
- https://www.esentire.com/security-advisories/netsupport-rat-clickfix-distribution
- https://www.scpx.com.au/2025/11/16/decades-old-finger-protocol-abused-in-clickfix-malware-attacks/ # filefix variant
author: montysecurity, Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-11-19
tags:
- attack.execution
- attack.t1204.001
- attack.t1204.004
logsource:
category: process_creation
product: windows
detection:
selection_parent:
ParentImage|endswith: '\explorer.exe'
CommandLine|contains: '#'
selection_cli_captcha:
CommandLine|contains:
- 'account'
- 'anti-bot'
- 'botcheck'
- 'captcha'
- 'challenge'
- 'confirmation'
- 'fraud'
- 'human'
- 'identification'
- 'identificator'
- 'identity'
- 'robot'
- 'validation'
- 'verification'
- 'verify'
condition: all of selection_*
falsepositives:
- Unlikely
level: high
high
Suspicious Explorer Process with Whitespace Padding - ClickFix/FileFix
Detects process creation with suspicious whitespace padding followed by a '#' character, which may indicate ClickFix or FileFix techniques used to conceal malicious commands from visual inspection.
ClickFix and FileFix are social engineering attack techniques where adversaries distribute phishing documents or malicious links that deceive users into opening the Windows Run dialog box or File Explorer search bar.
The victims are then instructed to paste commands from their clipboard, which contain extensive whitespace padding using various Unicode space characters to push the actual malicious command far to the right, effectively hiding it from immediate view.
status experimentalauthor Swachchhanda Shrawan Poudel (Nextron Systems)id 3ae9974a-eb09-4044-8e70-8980a50c12c8
view Sigma YAML
title: Suspicious Explorer Process with Whitespace Padding - ClickFix/FileFix
id: 3ae9974a-eb09-4044-8e70-8980a50c12c8
related:
- id: 8f2a5c3d-9e4b-4a7c-8d1f-2e5a6b9c3d7e
type: similar
- id: 7a1b4c5e-8f3d-4b9a-7c2e-1f4a5b8c6d9e
type: similar
status: experimental
description: |
Detects process creation with suspicious whitespace padding followed by a '#' character, which may indicate ClickFix or FileFix techniques used to conceal malicious commands from visual inspection.
ClickFix and FileFix are social engineering attack techniques where adversaries distribute phishing documents or malicious links that deceive users into opening the Windows Run dialog box or File Explorer search bar.
The victims are then instructed to paste commands from their clipboard, which contain extensive whitespace padding using various Unicode space characters to push the actual malicious command far to the right, effectively hiding it from immediate view.
references:
- https://expel.com/blog/cache-smuggling-when-a-picture-isnt-a-thousand-words/
- https://mrd0x.com/filefix-clickfix-alternative/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-11-04
modified: 2025-11-26
tags:
- attack.execution
- attack.stealth
- attack.t1204.004
- attack.t1027.010
logsource:
category: process_creation
product: windows
detection:
selection_explorer:
ParentImage|endswith: '\explorer.exe'
CommandLine|contains: '#'
selection_space_variation:
CommandLine|contains:
- ' ' # En Quad (U+2000)
- ' ' # Em Quad (U+2001)
- ' ' # En Space (U+2002)
- ' ' # Em Space (U+2003)
- ' ' # Three-Per-Em Space (U+2004)
- ' ' # Four-Per-Em Space (U+2005)
- ' ' # Six-Per-Em Space (U+2006)
- ' ' # Figure Space (U+2007)
- ' ' # Punctuation Space (U+2008)
- ' ' # Thin Space (U+2009)
- ' ' # Hair Space (U+200A)
- ' ' # No-Break Space (U+00A0)
- ' ' # Normal space (0x20)
condition: all of selection_*
falsepositives:
- Unknown
level: high
high
Suspicious FileFix Execution Pattern
Detects suspicious FileFix execution patterns where users are tricked into running malicious commands through browser file upload dialog manipulation.
This attack typically begins when users visit malicious websites impersonating legitimate services or news platforms,
which may display fake CAPTCHA challenges or direct instructions to open file explorer and paste clipboard content.
The clipboard content usually contains commands that download and execute malware, such as information stealing tools.
status experimentalauthor 0xFustang, Swachchhanda Shrawan Poudel (Nextron Systems)id b5b29e4e-31fa-4fdf-b058-296e7a1aa0c2
view Sigma YAML
title: Suspicious FileFix Execution Pattern
id: b5b29e4e-31fa-4fdf-b058-296e7a1aa0c2
related:
- id: 4fee3d51-8069-4a4c-a0f7-924fcaff2c70
type: similar
- id: 4be03877-d5b6-4520-85c9-a5911c0a656c
type: obsolete
status: experimental
description: |
Detects suspicious FileFix execution patterns where users are tricked into running malicious commands through browser file upload dialog manipulation.
This attack typically begins when users visit malicious websites impersonating legitimate services or news platforms,
which may display fake CAPTCHA challenges or direct instructions to open file explorer and paste clipboard content.
The clipboard content usually contains commands that download and execute malware, such as information stealing tools.
references:
- https://mrd0x.com/filefix-clickfix-alternative/
- https://expel.com/blog/cache-smuggling-when-a-picture-isnt-a-thousand-words/ # phishing lure directly asking users to open file explorer and paste command
- https://blog.checkpoint.com/research/filefix-the-new-social-engineering-attack-building-on-clickfix-tested-in-the-wild/
author: 0xFustang, Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-11-24
tags:
- attack.execution
- attack.t1204.004
logsource:
category: process_creation
product: windows
detection:
selection_exec_parent:
# This is case where phishing pages trick users to paste commands in browser file upload dialog
ParentImage|endswith:
- '\brave.exe'
- '\chrome.exe'
- '\firefox.exe'
- '\msedge.exe'
CommandLine|contains: '#'
selection_cli_lolbin:
CommandLine|contains:
- '%comspec%'
- 'bitsadmin'
- 'certutil'
- 'cmd'
- 'cscript'
- 'curl'
- 'finger'
- 'mshta'
- 'powershell'
- 'pwsh'
- 'regsvr32'
- 'rundll32'
- 'schtasks'
- 'wget'
- 'wscript'
selection_cli_captcha:
CommandLine|contains:
- 'account'
- 'anti-bot'
- 'botcheck'
- 'captcha'
- 'challenge'
- 'confirmation'
- 'fraud'
- 'human'
- 'identification'
- 'identificator'
- 'identity'
- 'robot'
- 'validation'
- 'verification'
- 'verify'
condition: selection_exec_parent and 1 of selection_cli_*
falsepositives:
- Legitimate use of PowerShell or other utilities launched from browser extensions or automation tools
level: high
high
Suspicious Space Characters in RunMRU Registry Path - ClickFix
Detects the occurrence of numerous space characters in RunMRU registry paths, which may indicate execution via phishing lures using clickfix techniques to hide malicious commands in the Windows Run dialog box from naked eyes.
status experimentalauthor Swachchhanda Shrawan Poudel (Nextron Systems)id 7a1b4c5e-8f3d-4b9a-7c2e-1f4a5b8c6d9e
view Sigma YAML
title: Suspicious Space Characters in RunMRU Registry Path - ClickFix
id: 7a1b4c5e-8f3d-4b9a-7c2e-1f4a5b8c6d9e
related:
- id: 3ae9974a-eb09-4044-8e70-8980a50c12c8
type: similar
status: experimental
description: |
Detects the occurrence of numerous space characters in RunMRU registry paths, which may indicate execution via phishing lures using clickfix techniques to hide malicious commands in the Windows Run dialog box from naked eyes.
references:
- https://expel.com/blog/cache-smuggling-when-a-picture-isnt-a-thousand-words/
- https://github.com/JohnHammond/recaptcha-phish
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-11-04
tags:
- attack.execution
- attack.stealth
- attack.t1204.004
- attack.t1027.010
logsource:
category: registry_set
product: windows
detection:
selection_key:
TargetObject|contains: '\Software\Microsoft\Windows\CurrentVersion\Explorer\RunMRU\'
Details|contains: '#'
selection_space_variation:
Details|contains:
- ' ' # En Quad (U+2000)
- ' ' # Em Quad (U+2001)
- ' ' # En Space (U+2002)
- ' ' # Em Space (U+2003)
- ' ' # Three-Per-Em Space (U+2004)
- ' ' # Four-Per-Em Space (U+2005)
- ' ' # Six-Per-Em Space (U+2006)
- ' ' # Figure Space (U+2007)
- ' ' # Punctuation Space (U+2008)
- ' ' # Thin Space (U+2009)
- ' ' # Hair Space (U+200A)
- ' ' # No-Break Space (U+00A0)
- ' ' # Normal space
condition: all of selection_*
falsepositives:
- Unlikely
level: high
high
Suspicious Space Characters in TypedPaths Registry Path - FileFix
Detects the occurrence of numerous space characters in TypedPaths registry paths, which may indicate execution via phishing lures using file-fix techniques to hide malicious commands.
status experimentalauthor Swachchhanda Shrawan Poudel (Nextron Systems)id 8f2a5c3d-9e4b-4a7c-8d1f-2e5a6b9c3d7e
view Sigma YAML
title: Suspicious Space Characters in TypedPaths Registry Path - FileFix
id: 8f2a5c3d-9e4b-4a7c-8d1f-2e5a6b9c3d7e
related:
- id: 3ae9974a-eb09-4044-8e70-8980a50c12c8
type: similar
status: experimental
description: |
Detects the occurrence of numerous space characters in TypedPaths registry paths, which may indicate execution via phishing lures using file-fix techniques to hide malicious commands.
references:
- https://expel.com/blog/cache-smuggling-when-a-picture-isnt-a-thousand-words/
- https://mrd0x.com/filefix-clickfix-alternative/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-11-04
tags:
- attack.execution
- attack.stealth
- attack.t1204.004
- attack.t1027.010
logsource:
category: registry_set
product: windows
detection:
selection_key:
TargetObject|endswith: '\Software\Microsoft\Windows\CurrentVersion\Explorer\TypedPaths\url1'
Details|contains: '#'
selection_space_variation:
Details|contains:
- ' ' # En Quad (U+2000)
- ' ' # Em Quad (U+2001)
- ' ' # En Space (U+2002)
- ' ' # Em Space (U+2003)
- ' ' # Three-Per-Em Space (U+2004)
- ' ' # Four-Per-Em Space (U+2005)
- ' ' # Six-Per-Em Space (U+2006)
- ' ' # Figure Space (U+2007)
- ' ' # Punctuation Space (U+2008)
- ' ' # Thin Space (U+2009)
- ' ' # Hair Space (U+200A)
- ' ' # No-Break Space (U+00A0)
- ' ' # Normal space
condition: all of selection_*
falsepositives:
- Unlikely
level: high