Detectionhighexperimental

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.

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Launch

Swachchhanda Shrawan Poudel (Nextron Systems)Created Tue Nov 047a1b4c5e-8f3d-4b9a-7c2e-1f4a5b8c6d9ewindows

Log Source

WindowsRegistry Set

ProductWindows← raw: windows

CategoryRegistry Set← raw: registry_set

Detection Logic

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_*

False Positives

Unlikely

False positives are unlikely for most environments. High confidence detection.

References

MITRE ATT&CK

Tactics

TA0002 · Execution TA0005 · Defense Evasion

Sub-techniques

T1027.010 · Command Obfuscation

Other

attack.t1204.004

Related Rules

SimilarDetectionhigh

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.

Detects similar activity. Both rules may fire on overlapping events.

Rule Metadata

Rule ID

7a1b4c5e-8f3d-4b9a-7c2e-1f4a5b8c6d9e

Status

experimental

Level

high

Type

Detection

Created

Tue Nov 04

Author

Swachchhanda Shrawan Poudel (Nextron Systems)

Path

rules/windows/registry/registry_set/registry_set_susp_runmru_space_character.yml

Raw Tags

attack.executionattack.t1204.004attack.defense-evasionattack.t1027.010

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