YARA · Volexity threat-intel

VOLEXITY_Apt_Delivery_Win_Charming_Openvpn_Client

Detects a fake OpenVPN client developed by CharmingCypress.

APT / threat actorVolexity threat-intelBSD 2-Clause LicenseCompiles with YARA-X

Author: threatintel@volexity.com
Date: 2023-10-17
Modified: 2023-10-27
Score / Quality: 75 / 80

What this rule detects

Detects a fake OpenVPN client developed by CharmingCypress.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-delivery-win-charming-openvpn-client.yarBSD 2-Clause License

rule VOLEXITY_Apt_Delivery_Win_Charming_Openvpn_Client : CHARMINGCYPRESS FILE
{
	meta:
		description = "Detects a fake OpenVPN client developed by CharmingCypress."
		author = "threatintel@volexity.com"
		id = "b69fdd72-4a55-5e83-b754-401fe9339007"
		date = "2023-10-17"
		modified = "2023-10-27"
		reference = "TIB-20231027"
		source_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/2024/2024-02-13 CharmingCypress/rules.yar#L299-L323"
		license_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/LICENSE.txt"
		hash = "2d99755d5cd25f857d6d3aa15631b69f570d20f95c6743574f3d3e3e8765f33c"
		logic_hash = "02596a62cb1ba17ecabef0ae93f434e4774b00422a6da2106a2bc4c59d2f8077"
		score = 75
		quality = 80
		tags = "CHARMINGCYPRESS, FILE"
		os = "win"
		os_arch = "all"
		scan_context = "file"
		severity = "critical"
		license = "See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt"
		rule_id = 9768
		version = 2

	strings:
		$s1 = "DONE!"
		$s2 = "AppCore.dll"
		$s3 = "ultralight@@"

	condition:
		all of ( $s* )
}

Strings (3 patterns)

Identifier	Type	Value
$s1	text	"DONE!"
$s2	text	"AppCore.dll"
$s3	text	"ultralight@@"

Condition

all of ( $s* )

In plain words (Heuristic)

All patterns in ( $s* ) must match.

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Sample hashes

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

2d99755d5cd25f857d6d3aa15631b69f570d20f95c6743574f3d3e3e8765f33c

Licence & attribution

Author: threatintel@volexity.com

Source repository: Volexity threat-intel @ 3a9d0b5245

Licence: BSD 2-Clause License (stated in the rule's own meta)

“See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt”

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: b69fdd72-4a55-5e83-b754-401fe9339007

Metadata

os	win
os_arch	all
scan_context	file
severity	critical
rule_id	9768
version	2

Tags:CHARMINGCYPRESS FILE

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