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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_Jdniexploit_Error_Indicators_Dec21_1

Detects error messages related to JDNI usage in log files that can indicate a Log4Shell / Log4j exploitation

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2021-12-10
Modified
2023-06-23
Score / Quality
70 / 85

What this rule detects

Detects error messages related to JDNI usage in log files that can indicate a Log4Shell / Log4j exploitation

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
susp-jdniexploit-error-indicators-dec21-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_Jdniexploit_Error_Indicators_Dec21_1
{
	meta:
		description = "Detects error messages related to JDNI usage in log files that can indicate a Log4Shell / Log4j exploitation"
		author = "Florian Roth (Nextron Systems)"
		id = "68bcf043-58b4-54a9-b024-64871b5d535f"
		date = "2021-12-10"
		modified = "2023-06-23"
		reference = "https://twitter.com/marcioalm/status/1470361495405875200?s=20"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_log4j_cve_2021_44228.yar#L213-L226"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "2ab98814b2ed66b0bda875fecc0b09db82035d7edcdb0af65f815817ec8c6cc8"
		score = 70
		quality = 85
		tags = ""

	strings:
		$x1 = "FATAL log4j - Message: BadAttributeValueException: "

	condition:
		1 of them
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$x1text"FATAL log4j - Message: BadAttributeValueException: "

Condition

1 of them

In plain words (Heuristic)

  • At least 1 patterns in the rule must match.

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References

Licence & attribution

Author: Florian Roth (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: 68bcf043-58b4-54a9-b024-64871b5d535f

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