locdoor_ransomware

YARA-2025-0823 Critical general Active

Rule to detect Locdoor/DryCry

locdoor_ransomware.yar Valid Syntax
rule locdoor_ransomware {

   meta:

      description = "Rule to detect Locdoor/DryCry"
      author = "Marc Rivero | @seifreed"
      reference = "https://twitter.com/leotpsc/status/1036180615744376832"

   strings:

      $s1 = "copy \"Locdoor.exe\" \"C:\\ProgramData\\Microsoft\\Windows\\Start Menu\\Programs\\StartUp\\temp00000000.exe\"" fullword ascii
      $s2 = "copy wscript.vbs C:\\ProgramData\\Microsoft\\Windows\\Start Menu\\Programs\\StartUp\\wscript.vbs" fullword ascii
      $s3 = "!! Your computer's important files have been encrypted! Your computer's important files have been encrypted!" fullword ascii
      $s4 = "echo CreateObject(\"SAPI.SpVoice\").Speak \"Your computer's important files have been encrypted! " fullword ascii    
      $s5 = "! Your computer's important files have been encrypted! " fullword ascii
      $s7 = "This program is not supported on your operating system." fullword ascii
      $s8 = "echo Your computer's files have been encrypted to Locdoor Ransomware! To make a recovery go to localbitcoins.com and create a wa" ascii
      $s9 = "Please enter the password." fullword ascii

   condition:

      ( uint16(0) == 0x5a4d and filesize < 600KB ) and all of them 
}

Rule Metadata

description
Rule to detect Locdoor/DryCry
author
Marc Rivero | @seifreed
reference
https://twitter.com/leotpsc/status/1036180615744376832

String Definitions

{"name":"$s1","value":"\"copy \\\"Locdoor.exe\\\" \\\"C:\\\\ProgramData\\\\Microsoft\\\\Windows\\\\Start Menu\\\\Programs\\\\StartUp\\\\temp00000000.exe\\\"\" fullword ascii"}
{"name":"$s2","value":"\"copy wscript.vbs C:\\\\ProgramData\\\\Microsoft\\\\Windows\\\\Start Menu\\\\Programs\\\\StartUp\\\\wscript.vbs\" fullword ascii"}
{"name":"$s3","value":"\"!! Your computer's important files have been encrypted! Your computer's important files have been encrypted!\" fullword ascii"}
{"name":"$s4","value":"\"echo CreateObject(\\\"SAPI.SpVoice\\\").Speak \\\"Your computer's important files have been encrypted! \" fullword ascii"}
{"name":"$s5","value":"\"! Your computer's important files have been encrypted! \" fullword ascii"}
{"name":"$s7","value":"\"This program is not supported on your operating system.\" fullword ascii"}
{"name":"$s8","value":"\"echo Your computer's files have been encrypted to Locdoor Ransomware! To make a recovery go to localbitcoins.com and create a wa\" ascii"}
{"name":"$s9","value":"\"Please enter the password.\" fullword ascii"}

Threat Analysis

This YARA rule is designed to detect general threats.

Severity Level: Critical

The rule uses pattern matching to identify specific byte sequences, strings, or behavioral patterns associated with malicious activity.

Detection Capabilities

  • File-based detection for executables and documents
  • Memory scanning for running processes
  • Network traffic analysis support

Command Line Usage

# Scan a single file
yara locdoor_ransomware.yar /path/to/suspicious/file

# Scan a directory recursively
yara -r locdoor_ransomware.yar /path/to/directory/

# Scan with metadata output
yara -m locdoor_ransomware.yar target_file

# Scan process memory (Linux)
yara locdoor_ransomware.yar /proc/[pid]/exe

Integration Examples

Python (yara-python)

import yara
rules = yara.compile(filepath='locdoor_ransomware.yar')
matches = rules.match('/path/to/file')

ClamAV Integration

clamscan --yara-rules=locdoor_ransomware.yar /path/to/scan

Rule Information

YARA ID
YARA-2025-0823
Created
August 19, 2025
Last Updated
August 19, 2025
Last Imported
Never

Threat Intelligence

Risk Level Critical
Category general
Detection Confidence Analysis Pending
False Positive Rate Not Available
Last Seen in Wild No Data

Export Options