YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_FE_APT_Backdoor_Linux32_SLOWPULSE_1

Detects samples mentioned in PulseSecure report

APT / threat actorSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: Mandiant
Date: 2021-04-16
Modified: 2023-12-05
Score / Quality: 75 / 85

What this rule detects

Detects samples mentioned in PulseSecure report

Targets: Linux ELF.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

fe-apt-backdoor-linux32-slowpulse-1.yarDetection Rule License 1.1

rule SIGNATURE_BASE_FE_APT_Backdoor_Linux32_SLOWPULSE_1 : FILE
{
	meta:
		description = "Detects samples mentioned in PulseSecure report"
		author = "Mandiant"
		id = "dd35257f-5b6f-55a6-a709-873ded1f4b72"
		date = "2021-04-16"
		modified = "2023-12-05"
		reference = "https://www.fireeye.com/blog/threat-research/2021/04/suspected-apt-actors-leverage-bypass-techniques-pulse-secure-zero-day.html"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_pulsesecure.yar#L227-L244"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "cd09ec795a8f4b6ced003500a44d810f49943514e2f92c81ab96c33e1c0fbd68"
		logic_hash = "c1d92ea4ed8e5934c8356e1e52092935c53a138e454026737448f7f523ea06be"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$sb1 = {FC b9 [4] e8 00 00 00 00 5? 8d b? [4] 8b}
		$sb2 = {f3 a6 0f 85 [4] b8 03 00 00 00 5? 5? 5?}
		$sb3 = {9c 60 e8 00 00 00 00 5? 8d [5] 85 ?? 0f 8?}
		$sb4 = {89 13 8b 51 04 89 53 04 8b 51 08 89 53 08}
		$sb5 = {8d [5] b9 [4] f3 a6 0f 8?}

	condition:
		(( uint32( 0 ) == 0x464c457f ) and ( uint8( 4 ) == 1 ) ) and all of them
}

Strings (5 patterns)

Identifier	Type	Value
$sb1	hex	{FC b9 [4] e8 00 00 00 00 5? 8d b? [4] 8b}
$sb2	hex	{f3 a6 0f 85 [4] b8 03 00 00 00 5? 5? 5?}
$sb3	hex	{9c 60 e8 00 00 00 00 5? 8d [5] 85 ?? 0f 8?}
$sb4	hex	{89 13 8b 51 04 89 53 04 8b 51 08 89 53 08}
$sb5	hex	{8d [5] b9 [4] f3 a6 0f 8?}

Condition

(( uint32( 0 ) == 0x464c457f ) and ( uint8( 4 ) == 1 ) ) 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

https://www.fireeye.com/blog/threat-research/2021/04/suspected-apt-actors-leverage-bypass-techniques-pulse-secure-zero-day.html

Sample hashes

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

cd09ec795a8f4b6ced003500a44d810f49943514e2f92c81ab96c33e1c0fbd68

Licence & attribution

Author: Mandiant

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: dd35257f-5b6f-55a6-a709-873ded1f4b72

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