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VOLEXITY_Apt_Malware_Win_Avburner

Detects AVBurner based on a combination of API calls used, hard-coded strings and bytecode patterns.

APT / threat actorVolexity threat-intelBSD 2-Clause LicenseCompiles with YARA-X
Author
threatintel@volexity.com
Date
2023-01-02
Modified
2024-08-16
Score / Quality
75 / 80

What this rule detects

Detects AVBurner based on a combination of API calls used, hard-coded strings and bytecode patterns.

It defines 14 patterns (8 text, 6 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

apt-malware-win-avburner.yarBSD 2-Clause License
rule VOLEXITY_Apt_Malware_Win_Avburner : DEVIOUSBAMBOO FILE MEMORY
{
	meta:
		description = "Detects AVBurner based on a combination of API calls used, hard-coded strings and bytecode patterns."
		author = "threatintel@volexity.com"
		id = "1bde0861-4820-5bb1-98a3-516092c91be0"
		date = "2023-01-02"
		modified = "2024-08-16"
		reference = "https://www.trendmicro.com/en_us/research/22/k/hack-the-real-box-apt41-new-subgroup-earth-longzhi.html"
		source_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/2023/2023-03-07 AVBurner/yara.yar#L1-L40"
		license_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/LICENSE.txt"
		hash = "4b1b1a1293ccd2c0fd51075de9376ebb55ab64972da785153fcb0a4eb523a5eb"
		logic_hash = "56ff6c8a4b737959a1219699a0457de1f0c34fead4299033840fb23c56a0caad"
		score = 75
		quality = 80
		tags = "DEVIOUSBAMBOO, FILE, MEMORY"
		os = "win"
		os_arch = "all"
		scan_context = "file,memory"
		severity = "critical"
		license = "See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt"
		rule_id = 8780
		version = 4

	strings:
		$api1 = "PspCreateProcessNotifyRoutineAddress" wide
		$api2 = "PspCreateThreadNotifyRoutineAddress" wide
		$api3 = "PspLoadImageNotifyRoutineAddress" wide
		$str1 = "\\\\.\\RTCORE64" wide
		$str2 = "\\\\%ws/pipe/%ws" wide
		$str3 = "CreateServerW Failed %u" wide
		$str4 = "OpenSCManager Failed %u" wide
		$str5 = "Get patternAddress" wide
		$pattern1 = { 4C 8B F9 48 8D 0C C1 E8 }
		$pattern2 = { 48 8D 0C DD 00 00 00 00  45 33 C0 49 03 CD 48 8B }
		$pattern3 = { 48 8D 04 C1 48 89 45 70 48 8B C8 E8 }
		$pattern4 = { 49 8D 0C FC 45 33 C0 48 8B D6 E8 00 00 00 00 00}
		$pattern5 = { 45 33 C0 48 8D 0C D9 48 8B D7 E8 00 00 00 00 00 00 00 00 00 00 00 00 00 }
		$pattern6 = { 41 0F BA 6D 00 0A BB 01 00 00 00 4C 8B F2 4C 8B F9 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 }

	condition:
		all of ( $api* ) or all of ( $str* ) or all of ( $pattern* )
}

Strings (14 patterns)

IdentifierTypeValueModifiers
$api1text"PspCreateProcessNotifyRoutineAddress"wide
$api2text"PspCreateThreadNotifyRoutineAddress"wide
$api3text"PspLoadImageNotifyRoutineAddress"wide
$str1text"\\\\.\\RTCORE64"wide
$str2text"\\\\%ws/pipe/%ws"wide
$str3text"CreateServerW Failed %u"wide
$str4text"OpenSCManager Failed %u"wide
$str5text"Get patternAddress"wide
$pattern1hex{ 4C 8B F9 48 8D 0C C1 E8 }
$pattern2hex{ 48 8D 0C DD 00 00 00 00 45 33 C0 49 03 CD 48 8B }
$pattern3hex{ 48 8D 04 C1 48 89 45 70 48 8B C8 E8 }
$pattern4hex{ 49 8D 0C FC 45 33 C0 48 8B D6 E8 00 00 00 00 00}
$pattern5hex{ 45 33 C0 48 8D 0C D9 48 8B D7 E8 00 00 00 00 00 00 00 00 00 00 00 00 00 }
$pattern6hex{ 41 0F BA 6D 00 0A BB 01 00 00 00 4C 8B F2 4C 8B F9 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 }

Condition

all of ( $api* ) or all of ( $str* ) or all of ( $pattern* )

In plain words (Heuristic)

  • All patterns in ( $api* ) must match.
  • All patterns in ( $str* ) must match.
  • All patterns in ( $pattern* ) 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).

  • 4b1b1a1293ccd2c0fd51075de9376ebb55ab64972da785153fcb0a4eb523a5eb

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”

Copyright notice: Copyright 2022 by Volexity, Inc.

Original rule

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

Rule id: 1bde0861-4820-5bb1-98a3-516092c91be0

Metadata

oswin
os_archall
scan_contextfile,memory
severitycritical
rule_id8780
version4

Tags:DEVIOUSBAMBOOFILEMEMORY