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DITEKSHEN_MALWARE_Win_Nemty

Detects Nemty/Nefilim ransomware

MalwareNemtyditekSHen 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 Nemty/Nefilim ransomware

Associated malware family: Nemty.

Targets: Windows PE.

It defines 17 patterns (17 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-win-nemty.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Nemty : FILE
{
	meta:
		description = "Detects Nemty/Nefilim ransomware"
		author = "ditekSHen"
		id = "361269c6-5215-5ecf-869c-3c55ff8387e1"
		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#L3553-L3577"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "dcebcddc472f4fb3bb34c35fc5a5424e54bfc3a262fdae10b189d210217b9b37"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$s1 = "Go build ID:" ascii
		$s2 = "GOMAXPROCSGetIfEntryGetVersionGlagoliticKharoshthiManichaeanOld_ItalicOld_PermicOld_TurkicOther_MathPOSTALCODEPhoenicianSaurasht" ascii
		$s3 = "crypto/x509.ExtKeyUsage" ascii
		$s4 = "crypto/x509.KeyUsageContentCommitment" ascii
		$s5 = "DEK-Info header" ascii
		$s6 = "GetUserProfileDirectoryWMagallanes Standard TimeMontevideo Standard TimeNorth Asia Standard TimePacific SA Standard TimeQueryPerformanceCounter" fullword ascii
		$s7 = "*( -  <  =  >  k= m=%: +00+03+04+05+06+07+08+09+10+11+12+13+14-01-02-03-04-05-06-08-09-11-12..." ascii
		$s8 = "Go cmd/compile go1.10" fullword ascii
		$s9 = ".dllprogramdatarecycle.bin" ascii
		$s10 = ".dll.exe.lnk.sys.url" ascii
		$vx1_1 = "Fa1led to os.OpenFile()" ascii
		$vx1_2 = "-HELP.txt" ascii
		$vf1_1 = "main.CTREncrypt" fullword ascii
		$vf1_2 = "main.FileSearch" fullword ascii
		$vf1_3 = "main.getdrives" fullword ascii
		$vf1_4 = "main.RSAEncrypt" fullword ascii
		$vf1_5 = "main.SaveNote" fullword ascii

	condition:
		uint16( 0 ) == 0x5a4d and ( 9 of ( $s* ) or ( all of ( $vx* ) and 2 of ( $s* ) ) or all of ( $vf* ) )
}

Strings (17 patterns)

IdentifierTypeValueModifiers
$s1text"Go build ID:"ascii
$s2text"GOMAXPROCSGetIfEntryGetVersionGlagoliticKharoshthiManichaeanOld_ItalicOld_PermicOld_TurkicOther_MathPOSTALCODEPhoenicianSaurasht"ascii
$s3text"crypto/x509.ExtKeyUsage"ascii
$s4text"crypto/x509.KeyUsageContentCommitment"ascii
$s5text"DEK-Info header"ascii
$s6text"GetUserProfileDirectoryWMagallanes Standard TimeMontevideo Standard TimeNorth Asia Standard TimePacific SA Standard TimeQueryPerformanceCounter"fullword ascii
$s7text"*( - < = > k= m=%: +00+03+04+05+06+07+08+09+10+11+12+13+14-01-02-03-04-05-06-08-09-11-12..."ascii
$s8text"Go cmd/compile go1.10"fullword ascii
$s9text".dllprogramdatarecycle.bin"ascii
$s10text".dll.exe.lnk.sys.url"ascii
$vx1_1text"Fa1led to os.OpenFile()"ascii
$vx1_2text"-HELP.txt"ascii
$vf1_1text"main.CTREncrypt"fullword ascii
$vf1_2text"main.FileSearch"fullword ascii
$vf1_3text"main.getdrives"fullword ascii
$vf1_4text"main.RSAEncrypt"fullword ascii
$vf1_5text"main.SaveNote"fullword ascii

Condition

uint16( 0 ) == 0x5a4d and ( 9 of ( $s* ) or ( all of ( $vx* ) and 2 of ( $s* ) ) or all of ( $vf* ) )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $vx* ) must match.
  • All patterns in ( $vf* ) must match.
  • At least 9 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: 361269c6-5215-5ecf-869c-3c55ff8387e1

Tags:FILE

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