YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_MAL_Hunting_LUA_SEASIDE_1

Hunting rule looking for strings observed in SEASIDE samples.

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

Author: Mandiant
Date: 2023-06-15
Modified: 2023-12-05
Score / Quality: 70 / 85

What this rule detects

Hunting rule looking for strings observed in SEASIDE samples.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-mal-hunting-lua-seaside-1.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_MAL_Hunting_LUA_SEASIDE_1 : FILE
{
	meta:
		description = "Hunting rule looking for strings observed in SEASIDE samples."
		author = "Mandiant"
		id = "86eaff7b-4ca0-53cd-8886-da66a36c778f"
		date = "2023-06-15"
		modified = "2023-12-05"
		reference = "https://www.mandiant.com/resources/blog/barracuda-esg-exploited-globally"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_barracuda_esg_unc4841_jun23.yar#L136-L152"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "cd2813f0260d63ad5adf0446253c2172"
		logic_hash = "82b61325a78bf8ab09d426cfadceb614a256dfcafb2e1f75595de63593ed2574"
		score = 70
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "function on_helo()"
		$s2 = "local bindex,eindex = string.find(helo,'.onion')"
		$s3 = "helosend = 'pd'..' '..helosend"
		$s4 = "os.execute(helosend)"

	condition:
		filesize < 1MB and all of ( $s* )
}

Strings (4 patterns)

Identifier	Type	Value
$s1	text	"function on_helo()"
$s2	text	"local bindex,eindex = string.find(helo,'.onion')"
$s3	text	"helosend = 'pd'..' '..helosend"
$s4	text	"os.execute(helosend)"

Condition

filesize < 1MB and all of ( $s* )

In plain words (Heuristic)

The file must be smaller than 1MB (a cheap guard that skips large files).
All patterns in ( $s* ) must match.

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Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

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References

https://www.mandiant.com/resources/blog/barracuda-esg-exploited-globally

Sample hashes

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

cd2813f0260d63ad5adf0446253c2172

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: 86eaff7b-4ca0-53cd-8886-da66a36c778f

Tags:FILE

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