YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_MAL_Macos_NK_3CX_Malicious_Samples_Mar23_1

Detects malicious macOS application related to 3CX compromise (decrypted payload)

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

Author: Florian Roth (Nextron Systems)
Date: 2023-03-30
Modified: 2023-12-05
Score / Quality: 80 / 85

What this rule detects

Detects malicious macOS application related to 3CX compromise (decrypted payload)

It defines 2 patterns (2 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-mal-macos-nk-3cx-malicious-samples-mar23-1.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_MAL_Macos_NK_3CX_Malicious_Samples_Mar23_1 : FILE
{
	meta:
		description = "Detects malicious macOS application related to 3CX compromise (decrypted payload)"
		author = "Florian Roth (Nextron Systems)"
		id = "ff39e577-7063-5025-bead-68394a86c87c"
		date = "2023-03-30"
		modified = "2023-12-05"
		reference = "https://www.reddit.com/r/crowdstrike/comments/125r3uu/20230329_situational_awareness_crowdstrike/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_mal_3cx_compromise_mar23.yar#L168-L184"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "b86c695822013483fa4e2dfdf712c5ee777d7b99cbad8c2fa2274b133481eadb"
		hash = "ac99602999bf9823f221372378f95baa4fc68929bac3a10e8d9a107ec8074eca"
		hash = "51079c7e549cbad25429ff98b6d6ca02dc9234e466dd9b75a5e05b9d7b95af72"
		logic_hash = "c2733c2f7dcca82e5a0b2301777fb54853d04dfa893bcf88ecbec34d37e1a38a"
		score = 80
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "20230313064152Z0"
		$s2 = "Developer ID Application: 3CX (33CF4654HL)"

	condition:
		( uint16( 0 ) == 0xfeca or uint16( 0 ) == 0xfacf or uint32( 0 ) == 0xbebafeca ) and all of them
}

Strings (2 patterns)

Identifier	Type	Value	Modifiers
$s1	text	"20230313064152Z0"
$s2	text	"Developer ID Application: 3CX (33CF4654HL)"

Condition

( uint16( 0 ) == 0xfeca or uint16( 0 ) == 0xfacf or uint32( 0 ) == 0xbebafeca ) and all of them

In plain words (Heuristic)

All patterns in the rule must match.

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References

https://www.reddit.com/r/crowdstrike/comments/125r3uu/20230329_situational_awareness_crowdstrike/

Sample hashes

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

b86c695822013483fa4e2dfdf712c5ee777d7b99cbad8c2fa2274b133481eadb
ac99602999bf9823f221372378f95baa4fc68929bac3a10e8d9a107ec8074eca
51079c7e549cbad25429ff98b6d6ca02dc9234e466dd9b75a5e05b9d7b95af72

Licence & attribution

Author: Florian Roth (Nextron Systems)

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: ff39e577-7063-5025-bead-68394a86c87c

Tags:FILE

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