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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_Cisco_LINE_VIPER_RSA_Enc_Random_AES_Key_Gen

Detects LINE VIPER Cisco ASA malware code as part of RSA encrypted random AES key generation.

MalwareSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
NCSC
Date
2025-09-25
Modified
2026-05-15
Score / Quality
85 / 85

What this rule detects

Detects LINE VIPER Cisco ASA malware code as part of RSA encrypted random AES key generation.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-cisco-line-viper-rsa-enc-random-aes-key-gen.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_Cisco_LINE_VIPER_RSA_Enc_Random_AES_Key_Gen
{
	meta:
		description = "Detects LINE VIPER Cisco ASA malware code as part of RSA encrypted random AES key generation."
		author = "NCSC"
		id = "ef37a3cf-aab8-513b-b859-7f7704fce622"
		date = "2025-09-25"
		modified = "2026-05-15"
		reference = "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_cisco_asa_lineviper_rayinitiator_sep25.yar#L125-L154"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "c382158e21300f49ed3da58e3e02c4578c10fd854c87a18227a01b7d6f7723bc"
		score = 85
		quality = 85
		tags = ""

	strings:
		$xc1 = {
         48 31 C0 49 89 06 49 89 46 08 49 83 C6 10 49 83 ED 10
         4D 85 ED 75 D8 BF 30 00 00 00
      }
		$xc2 = {
         0F 85 57 01 00 00 49 8B 44 24 08 48 83 F8 2F 7C 33 41
         BD F0 02 00 00 4D 8D 74 24 10 49 8B 3E
      }
		$xc3 = {
         85 C0 0F 8E EE 00 00 00 41 BD F0 02 00 00 4D 8D 7C 24
         10 49 8B 3F 48 85 FF 74 0D 49 83 C7 10 49 83 ED 10 4D 85 ED 75 EB
         4D 89 37 BF 70 00 00 00
      }
		$xc4 = {
         48 85 C0 0F 84 3F 00 00 00 48 89 45 B0 BF 80 00 00 00
         4C 89 EE 48 89 C2 48 8B 4D A8 41 B8 01 00 00 00
      }

	condition:
		1 of them
}

Strings (4 patterns)

IdentifierTypeValueModifiers
$xc1hex{ 48 31 C0 49 89 06 49 89 46 08 49 83 C6 10 49 83 ED 10 4D 85 ED 75 D8 BF 30 00 00 00 }
$xc2hex{ 0F 85 57 01 00 00 49 8B 44 24 08 48 83 F8 2F 7C 33 41 BD F0 02 00 00 4D 8D 74 24 10 49 8B 3E }
$xc3hex{ 85 C0 0F 8E EE 00 00 00 41 BD F0 02 00 00 4D 8D 7C 24 10 49 8B 3F 48 85 FF 74 0D 49 83 C7 10 49 83 ED 10 4D 85 ED 75 EB 4D 89 37 BF …
$xc4hex{ 48 85 C0 0F 84 3F 00 00 00 48 89 45 B0 BF 80 00 00 00 4C 89 EE 48 89 C2 48 8B 4D A8 41 B8 01 00 00 00 }

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: NCSC

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: ef37a3cf-aab8-513b-b859-7f7704fce622

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