Suspicious LNK Command-Line Padding with Whitespace Characters

Swachchhanda Shrawan Poudel (Nextron Systems)

Detects exploitation of LNK file command-line length discrepancy, where attackers hide malicious 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 malicious 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 suspicious use of such padding observed in real-world attacks.

2025-03-19 00:00:00

None

dd8756e7-a3a0-4768-b47e-8f545d1a751c

attack.initial-access attack.execution attack.t1204.002

Community Rule

Swachchhanda Shrawan Poudel

Merge PR #5240 from @swachchhanda000 - Add `Suspicious LNK Command-Line Padding with Whitespace Characters`

2025-04-17