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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_EXPL_LOG_CVE_2021_27065_Exchange_Forensic_Artefacts_Mar21_1

Detects forensic artefacts found in HAFNIUM intrusions exploiting CVE-2021-27065

ExploitSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2021-03-02
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects forensic artefacts found in HAFNIUM intrusions exploiting CVE-2021-27065

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
expl-log-cve-2021-27065-exchange-forensic-artefacts-mar21-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_EXPL_LOG_CVE_2021_27065_Exchange_Forensic_Artefacts_Mar21_1 : LOG CVE_2021_27065
{
	meta:
		description = "Detects forensic artefacts found in HAFNIUM intrusions exploiting CVE-2021-27065"
		author = "Florian Roth (Nextron Systems)"
		id = "dcc1f741-cab0-5a0b-a261-a6bd05989723"
		date = "2021-03-02"
		modified = "2023-12-05"
		reference = "https://www.volexity.com/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerabilities/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_hafnium_log_sigs.yar#L2-L13"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "9306cf177928266ea921461e9da80ad5bb37e1e0848559898a414956cfbc2b49"
		score = 75
		quality = 85
		tags = "LOG, CVE-2021-27065"

	strings:
		$s1 = "S:CMD=Set-OabVirtualDirectory.ExternalUrl='" ascii wide fullword

	condition:
		1 of them
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$s1text"S:CMD=Set-OabVirtualDirectory.ExternalUrl='"ascii wide fullword

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: dcc1f741-cab0-5a0b-a261-a6bd05989723

Tags:LOGCVE_2021_27065

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