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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_Cisco_Rayinitiator_Stage_3

Detects RayInitiator GRUB bootkit stage 3 install phase code that searches for the 'client-cert-fail' string.

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 RayInitiator GRUB bootkit stage 3 install phase code that searches for the 'client-cert-fail' string.

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

Summary generated from the rule's metadata and condition.

Rule source

mal-cisco-rayinitiator-stage-3.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_Cisco_Rayinitiator_Stage_3
{
	meta:
		description = "Detects RayInitiator GRUB bootkit stage 3 install phase code that searches for the 'client-cert-fail' string."
		author = "NCSC"
		id = "ea42c20b-7362-5d2d-9ce2-ad010f3f880d"
		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#L41-L58"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "332756bc77cc17c3330ce1ffb0af9d1a7c0f5f9a457f7e9ad7f4081d7aba50c6"
		score = 85
		quality = 85
		tags = ""

	strings:
		$xc1 = {
         48 81 EE 00 00 00 08 48 B8 63 6C 69 65 6E 74 2D 63 49
         B8 65 72 74 2D 66 61 69 6C 48 FF C6 48 39 D6 0F 87 D2
         00 00 00 48 8B 3E 48 39 C7
      }

	condition:
		$xc1
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$xc1hex{ 48 81 EE 00 00 00 08 48 B8 63 6C 69 65 6E 74 2D 63 49 B8 65 72 74 2D 66 61 69 6C 48 FF C6 48 39 D6 0F 87 D2 00 00 00 48 8B 3E 48 39 …

Condition

$xc1

In plain words (Heuristic)

  • Pattern $xc1 must be present.

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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: ea42c20b-7362-5d2d-9ce2-ad010f3f880d