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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_BAT_OBFUSC_Jul24_2

Detects indicators of obfuscation in Windows Batch files

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2024-07-12
Modified
2024-12-12
Score / Quality
70 / 85

What this rule detects

Detects indicators of obfuscation in Windows Batch files

It defines 1 patterns (1 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
susp-bat-obfusc-jul24-2.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_BAT_OBFUSC_Jul24_2 : FILE
{
	meta:
		description = "Detects indicators of obfuscation in Windows Batch files"
		author = "Florian Roth"
		id = "999cd365-2862-5618-b0b6-ee45dea1e9cf"
		date = "2024-07-12"
		modified = "2024-12-12"
		reference = "https://x.com/0xToxin/status/1811656147943752045"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/susp_bat_obfusc_jul24.yar#L18-L35"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "729ec93d180bf39c146c3fd847655340428abc3231b556ca51d3ca68825e7c3e"
		score = 70
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "&&set "

	condition:
		filesize < 300KB and #s1 > 30 and uint16( filesize -2 ) == 0x0a0d and uint8( filesize -3 ) == 0x25
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$s1text"&&set "

Condition

filesize < 300KB and #s1 > 30 and uint16( filesize -2 ) == 0x0a0d and uint8( filesize -3 ) == 0x25

In plain words (Heuristic)

  • The file must be smaller than 300KB (a cheap guard that skips large files).
  • Pattern $s1 must occur > 30 times.

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References

Licence & attribution

Author: Florian Roth

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: 999cd365-2862-5618-b0b6-ee45dea1e9cf

Tags:FILE

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