Suspicious LNK Command-Line Padding with Whitespace Characters (via process_creation)

This rule detects exploitation of LNK file command-line length discrepancy, where adversaries hide hostile commands beyond the 260-character UI limit while the actual command-line argument field supports 4096 characters using whitespace padding (e.g., 0x20, 0x09-0x0D). Adversaries insert non-printable whitespace characters (e.g., Line Feed \x0A, Carriage Return \x0D) to pad the visible section of the LNK file, pushing hostile commands past the UI-visible boundary. The hidden payload, executed at runtime but invisible in Windows Explorer properties, enables stealthy execution and evasion—commonly used for social engineering attacks. This rule flags anomalous use of such padding observed in real-world attacks.

SigmahighWindowsv1
Full detection rule

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Known false positives

  • Unknown

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.