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.
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Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.
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_*False positive likelihood has not been assessed. Additional context may be needed during triage.
Sub-techniques
Other
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.
Detects similar activity. Both rules may fire on overlapping events.
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.
Detects similar activity. Both rules may fire on overlapping events.