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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_LOG_CVE_2021_27065_Exchange_Forensic_Artefacts_Mar21_2

Detects suspicious log entries that indicate requests as described in reports on HAFNIUM activity

ExploitSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2021-03-10
Modified
2023-12-05
Score / Quality
65 / 85

What this rule detects

Detects suspicious log entries that indicate requests as described in reports on HAFNIUM activity

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
log-cve-2021-27065-exchange-forensic-artefacts-mar21-2.yarDetection Rule License 1.1
rule SIGNATURE_BASE_LOG_CVE_2021_27065_Exchange_Forensic_Artefacts_Mar21_2 : LOG
{
	meta:
		description = "Detects suspicious log entries that indicate requests as described in reports on HAFNIUM activity"
		author = "Florian Roth (Nextron Systems)"
		id = "37a26def-b360-518e-a4ab-9604a5b39afd"
		date = "2021-03-10"
		modified = "2023-12-05"
		reference = "https://www.praetorian.com/blog/reproducing-proxylogon-exploit/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_hafnium_log_sigs.yar#L92-L104"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "13e2e46689bc0e87c3cf13dc2ce213c384afe6c03c21e62a467974a0518c12da"
		score = 65
		quality = 85
		tags = "LOG"

	strings:
		$sr1 = /GET \/rpc\/ &CorrelationID=<empty>;&RequestId=[^\n]{40,600} (200|301|302)/

	condition:
		$sr1
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$sr1regex/GET \/rpc\/ &CorrelationID=<empty>;&RequestId=[^\n]{40,600} (200|301|302)/

Condition

$sr1

In plain words (Heuristic)

  • Pattern $sr1 must be present.

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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: 37a26def-b360-518e-a4ab-9604a5b39afd

Tags:LOG

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