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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_Sandworm_Cyclopsblink_Handle_Mod_0Xf_Command

Detects the code bytes used to check module ID 0xf control flags and a format string used for file content upload

APT / threat actorSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
NCSC
Date
2022-02-23
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects the code bytes used to check module ID 0xf control flags and a format string used for file content upload

Targets: Linux ELF.

It defines 5 patterns (1 text, 4 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
apt-sandworm-cyclopsblink-handle-mod-0xf-command.yarDetection Rule License 1.1
rule SIGNATURE_BASE_APT_Sandworm_Cyclopsblink_Handle_Mod_0Xf_Command : FILE
{
	meta:
		description = "Detects the code bytes used to check module ID 0xf control flags and a format string used for file content upload"
		author = "NCSC"
		id = "36646b7a-389d-5fd9-88a1-e43e7224763a"
		date = "2022-02-23"
		modified = "2023-12-05"
		reference = "https://www.ncsc.gov.uk/news/joint-advisory-shows-new-sandworm-malware-cyclops-blink-replaces-vpnfilter"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_sandworm_cyclops_blink.yar#L128-L150"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "3adf9a59743bc5d8399f67cab5eb2daf28b9b863"
		hash = "c59bc17659daca1b1ce65b6af077f86a648ad8a8"
		logic_hash = "6e3eebe404c8cd24e1e16eb3c881b1eda78ba6b365bf89c2557329e6f89396ac"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$ = {54 00 06 3E 54 00 07 FE 54 00 06 3E 2F 80 00 00}
		$ = {54 00 06 3E 54 00 07 BC 2F 80 00 00}
		$ = {54 00 06 3E 54 00 07 7A 2F 80 00 00}
		$ = {54 00 06 3E 54 00 06 F6 2F 80 00 00}
		$ = "file:%s\n" fullword

	condition:
		( uint32( 0 ) == 0x464c457f ) and ( all of them )
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$hex{54 00 06 3E 54 00 07 FE 54 00 06 3E 2F 80 00 00}
$hex{54 00 06 3E 54 00 07 BC 2F 80 00 00}
$hex{54 00 06 3E 54 00 07 7A 2F 80 00 00}
$hex{54 00 06 3E 54 00 06 F6 2F 80 00 00}
$text"file:%s\n"fullword

Condition

( uint32( 0 ) == 0x464c457f ) and ( all of them )

In plain words (Heuristic)

  • The file must start with the ELF header — a Linux/Unix executable.
  • All patterns in the rule must match.

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References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • 3adf9a59743bc5d8399f67cab5eb2daf28b9b863
  • c59bc17659daca1b1ce65b6af077f86a648ad8a8

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: 36646b7a-389d-5fd9-88a1-e43e7224763a

Tags:FILE

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