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DITEKSHEN_MALWARE_Win_Jennlog

Detects JennLog loader

MalwareJennlogditekSHen detectionBSD 2-Clause LicenseCompiles with YARA-X
Author
ditekSHen
Date
2020-11-06
Modified
2024-11-01
Score / Quality
75 / 75

What this rule detects

Detects JennLog loader

Associated malware family: Jennlog.

Targets: Windows PE.

It defines 9 patterns (9 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-win-jennlog.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Jennlog : FILE
{
	meta:
		description = "Detects JennLog loader"
		author = "ditekSHen"
		id = "38f8cd13-f157-5cce-bf04-80c29d254144"
		date = "2020-11-06"
		modified = "2024-11-01"
		reference = "https://github.com/ditekshen/detection"
		source_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/yara/malware.yar#L7980-L7996"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "085a4783c7c01ec95491d9999d1835ad9ab3dc70d77b944578e097b3ffe3a627"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$x1 = "%windir%\\system32\\rundll32.exe advapi32.dll,ProcessIdleTasks" fullword wide
		$x2 = "https://fkpageintheworld342.com" fullword wide
		$s1 = "ExecuteInstalledNodeAndDelete" fullword ascii
		$s2 = "ProcessExsist" fullword ascii
		$s3 = "helloworld.Certificate.txt" fullword wide
		$s4 = "ASCII85 encoded data should begin with '" fullword wide
		$s5 = "] WinRE config file path: C:\\" ascii
		$s6 = "] Parameters: configWinDir: NULL" ascii
		$s7 = "] Update enhanced config info is enabled." ascii

	condition:
		uint16( 0 ) == 0x5a4d and ( ( 1 of ( $x* ) and 3 of ( $s* ) ) or 5 of ( $s* ) or ( all of ( $x* ) and 2 of ( $s* ) ) )
}

Strings (9 patterns)

IdentifierTypeValueModifiers
$x1text"%windir%\\system32\\rundll32.exe advapi32.dll,ProcessIdleTasks"fullword wide
$x2text"https://fkpageintheworld342.com"fullword wide
$s1text"ExecuteInstalledNodeAndDelete"fullword ascii
$s2text"ProcessExsist"fullword ascii
$s3text"helloworld.Certificate.txt"fullword wide
$s4text"ASCII85 encoded data should begin with '"fullword wide
$s5text"] WinRE config file path: C:\\"ascii
$s6text"] Parameters: configWinDir: NULL"ascii
$s7text"] Update enhanced config info is enabled."ascii

Condition

uint16( 0 ) == 0x5a4d and ( ( 1 of ( $x* ) and 3 of ( $s* ) ) or 5 of ( $s* ) or ( all of ( $x* ) and 2 of ( $s* ) ) )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $x* ) must match.
  • At least 1 patterns in ( $x* ) must match.
  • At least 3 patterns in ( $s* ) must match.
  • At least 5 patterns in ( $s* ) must match.
  • At least 2 patterns in ( $s* ) must match.

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References

Licence & attribution

Author: ditekSHen

Source repository: ditekSHen detection @ e76c93dcde

Licence: BSD 2-Clause License (repository licence)

Copyright notice: Copyright 2021 by ditekSHen (https://github.com/ditekshen/detection).

Original rule

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

Rule id: 38f8cd13-f157-5cce-bf04-80c29d254144

Tags:FILE