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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_MAL_Macos_NK_3CX_DYLIB_Mar23_1

Detects malicious DYLIB files related to 3CX compromise

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 DYLIB files related to 3CX compromise

It defines 3 patterns (0 text, 3 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

apt-mal-macos-nk-3cx-dylib-mar23-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_APT_MAL_Macos_NK_3CX_DYLIB_Mar23_1
{
	meta:
		description = "Detects malicious DYLIB files related to 3CX compromise"
		author = "Florian Roth (Nextron Systems)"
		id = "a19904d3-9b2d-561f-b734-20bf09584fa7"
		date = "2023-03-30"
		modified = "2023-12-05"
		reference = "https://www.sentinelone.com/blog/smoothoperator-ongoing-campaign-trojanizes-3cx-software-in-software-supply-chain-attack/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_mal_3cx_compromise_mar23.yar#L188-L214"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "a64fa9f1c76457ecc58402142a8728ce34ccba378c17318b3340083eeb7acc67"
		hash = "fee4f9dabc094df24d83ec1a8c4e4ff573e5d9973caa676f58086c99561382d7"
		logic_hash = "e52c76de1e995cc7084ddb390b60f4bc66e5bdf89aaa28ef3fd70578ed3145a6"
		score = 80
		quality = 85
		tags = ""

	strings:
		$xc1 = { 37 15 00 13 16 16 1B 55 4F 54 4A 5A 52 2D 13 14 
               1E 15 0D 09 5A 34 2E 5A 4B 4A 54 4A 41 5A 2D 13
               14 4C 4E 41 5A 02 4C 4E 53 5A 3B 0A 0A 16 1F 2D
               1F 18 31 13 0E 55 4F 49 4D 54 49 4C 5A 52 31 32
               2E 37 36 56 5A 16 13 11 1F 5A 3D 1F 19 11 15 53
               5A 39 12 08 15 17 1F 55 4B 4A 42 54 4A 54 4F 49
               4F 43 54 4B 48 42 5A 29 1B 1C 1B 08 13 55 4F 49
               4D 54 49 4C 7A }
		$xc2 = { 41 49 19 02 25 1b 0f 0e 12 25 0e 15 11 1f 14 25 19 15 14 0e 1f 14 0e 47 5f 09 41 25 25 0e 0f 0e 17 1b 47 }
		$xc3 = { 55 29 03 09 0e 1f 17 55 36 13 18 08 1b 08 03 55 39 15 08 1f 29 1f 08 0c 13 19 1f 09 55 29 03 09 0e 1f 17 2c 1f 08 09 13 15 14 54 0a 16 13 09 0e }

	condition:
		1 of them
}

Strings (3 patterns)

IdentifierTypeValueModifiers
$xc1hex{ 37 15 00 13 16 16 1B 55 4F 54 4A 5A 52 2D 13 14 1E 15 0D 09 5A 34 2E 5A 4B 4A 54 4A 41 5A 2D 13 14 4C 4E 41 5A 02 4C 4E 53 5A 3 …
$xc2hex{ 41 49 19 02 25 1b 0f 0e 12 25 0e 15 11 1f 14 25 19 15 14 0e 1f 14 0e 47 5f 09 41 25 25 0e 0f 0e 17 1b 47 }
$xc3hex{ 55 29 03 09 0e 1f 17 55 36 13 18 08 1b 08 03 55 39 15 08 1f 29 1f 08 0c 13 19 1f 09 55 29 03 09 0e 1f 17 2c 1f 08 09 13 15 14 54 0a 16 13 09 0e }

Condition

1 of them

In plain words (Heuristic)

  • At least 1 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).

  • a64fa9f1c76457ecc58402142a8728ce34ccba378c17318b3340083eeb7acc67
  • fee4f9dabc094df24d83ec1a8c4e4ff573e5d9973caa676f58086c99561382d7

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: a19904d3-9b2d-561f-b734-20bf09584fa7