YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_EXPL_HKTL_LNX_Dirtyfraglpe_May26

Detects dirtyfrag, a local privilege escalation exploit for Linux.

ExploitSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: Pezier Pierre-Henri (Nextron Systems)
Date: 2026-05-07
Modified: 2026-05-15
Score / Quality: 80 / 85

What this rule detects

Detects dirtyfrag, a local privilege escalation exploit for Linux.

Targets: Linux ELF.

It defines 6 patterns (4 text, 2 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

expl-hktl-lnx-dirtyfraglpe-may26.yarDetection Rule License 1.1

rule SIGNATURE_BASE_EXPL_HKTL_LNX_Dirtyfraglpe_May26 : FILE
{
	meta:
		description = "Detects dirtyfrag, a local privilege escalation exploit for Linux."
		author = "Pezier Pierre-Henri (Nextron Systems)"
		id = "7548b4c6-6b0f-5c05-acab-26dceac109ac"
		date = "2026-05-07"
		modified = "2026-05-15"
		reference = "https://github.com/V4bel/dirtyfrag/tree/master"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_lnx_dirtyfrag.yar#L1-L26"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "c35594d42f7a5d5d2895164147ee1bc62bb8e294c8468093b7d6fcaab0b174c8"
		logic_hash = "8b804b3f2d00eccb1f4208173fde15f0525ac710388f14d6a4f9844c49d3660e"
		score = 80
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "gained CAP_NET_RAW within netn" ascii
		$x2 = "DIRTYFRAG_VERBOSE" ascii
		$s1 = { 15 7C 4A 7F B9 79 37 9E }
		$s2 = "/proc/self/setgroups" ascii fullword
		$s3 = "pcbc(fcrypt)" ascii fullword
		$s4 = { 17 bb c7 f3 3f 36 ba 71 8e 97 65 60 69 b6 f6 e6 }

	condition:
		filesize < 100KB and uint32be( 0 ) == 0x7f454c46 and ( 1 of ( $x* ) or 3 of ( $s* ) )
}

Strings (6 patterns)

Identifier	Type	Value	Modifiers
$x1	text	"gained CAP_NET_RAW within netn"	ascii
$x2	text	"DIRTYFRAG_VERBOSE"	ascii
$s1	hex	{ 15 7C 4A 7F B9 79 37 9E }
$s2	text	"/proc/self/setgroups"	ascii fullword
$s3	text	"pcbc(fcrypt)"	ascii fullword
$s4	hex	{ 17 bb c7 f3 3f 36 ba 71 8e 97 65 60 69 b6 f6 e6 }

Condition

filesize < 100KB and uint32be( 0 ) == 0x7f454c46 and ( 1 of ( $x* ) or 3 of ( $s* ) )

In plain words (Heuristic)

The file must start with the ELF header — a Linux/Unix executable.
The file must be smaller than 100KB (a cheap guard that skips large files).
At least 1 patterns in ( $x* ) must match.
At least 3 patterns in ( $s* ) must match.

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References

https://github.com/V4bel/dirtyfrag/tree/master

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

c35594d42f7a5d5d2895164147ee1bc62bb8e294c8468093b7d6fcaab0b174c8

Licence & attribution

Author: Pezier Pierre-Henri (Nextron Systems)

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: 7548b4c6-6b0f-5c05-acab-26dceac109ac

Tags:FILE

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