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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_Emotet_BKA_Quarantine_Apr21

No description has been set in the source file - Signature Base

MalwareEmotetSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
press inquiries <info@bka.de>, technical contact <info@mha.bka.de>
Date
2021-03-23
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

No description has been set in the source file - Signature Base

Associated malware family: Emotet.

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

Summary generated from the rule's metadata and condition.

Rule source

mal-emotet-bka-quarantine-apr21.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_Emotet_BKA_Quarantine_Apr21
{
	meta:
		description = "No description has been set in the source file - Signature Base"
		author = "press inquiries <info@bka.de>, technical contact <info@mha.bka.de>"
		id = "22c27d82-00cb-5d2f-a1cc-9f8b4c60aecd"
		date = "2021-03-23"
		modified = "2023-12-05"
		reference = "https://www.bka.de/DE/IhreSicherheit/RichtigesVerhalten/StraftatenImInternet/FAQ/FAQ_node.html"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/crime_emotet.yar#L39-L52"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "cc75be5f641e21446a41bf9cc855330a612847e7e3a3be935577d33195f40d05"
		score = 75
		quality = 85
		tags = ""
		descripton = "The modified emotet binary replaces the original emotet on the system of the victim. The original emotet is copied to a quarantine for evidence-preservation."
		note = "The quarantine folder depends on the scope of the initial emotet infection (user or administrator). It is the temporary folder as returned by GetTempPathW under a filename starting with UDP as returned by GetTempFileNameW. To prevent accidental reinfection by a user, the quarantined emotet is encrypted using RC4 and a 0x20 bytes long key found at the start of the quarantined file (see $key)."
		sharing = "TLP:WHITE"

	strings:
		$key = { c3 da da 19 63 45 2c 86 77 3b e9 fd 24 64 fb b8 07 fe 12 d0 2a 48 13 38 48 68 e8 ae 91 3c ed 82 }

	condition:
		$key at 0
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$keyhex{ c3 da da 19 63 45 2c 86 77 3b e9 fd 24 64 fb b8 07 fe 12 d0 2a 48 13 38 48 68 e8 ae 91 3c ed 82 }

Condition

$key at 0

In plain words (Heuristic)

  • Pattern $key must be found at offset 0.

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References

Licence & attribution

Author: press inquiries <info@bka.de>, technical contact <info@mha.bka.de>

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: 22c27d82-00cb-5d2f-a1cc-9f8b4c60aecd

Metadata

descriptonThe modified emotet binary replaces the original emotet on the system of the victim. The original emotet is copied to a quarantine for evidence-preservation.
noteThe quarantine folder depends on the scope of the initial emotet infection (user or administrator). It is the temporary folder as returned by GetTempPathW under a filename starting with UDP as returned by GetTempFileNameW. To prevent accidental reinfection by a user, the quarantined emotet is encrypted using RC4 and a 0x20 bytes long key found at the start of the quarantined file (see $key).
sharingTLP:WHITE

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