Zombierat

Overview

ZombieRAT (also cataloged across antimalware archives as ZombieRat, Backdoor.Win32.ZombieRat, and Zombie RAT by The Bo$$) is an early-to-mid 2000s Remote Access Trojan created in Visual Basic around 2003 by a developer using the handle 'The Bo$$'. Operating under a client-server architecture, ZombieRAT allowed unauthorized operators to connect to infected Windows 9x, ME, and 2000 workstations over direct TCP network sockets. Upon initial execution, ZombieRAT copies its executable payload into the Windows System directory, establishes persistence by creating registry entries under the Windows Run key, and listens for inbound connections. The trojan provided operators with a graphical management console offering remote surveillance and control commands, including file system browsing, file transfer, registry tampering, remote process termination, keystroke interception, desktop viewing, and disruptive hardware routines.

Known aliases

Threat reports may refer to this family under multiple names:

• ZombieRAT
• Backdoor.Win32.ZombieRat
• Zombie RAT by The Bo$$
• ZombieRat 1.0
• Backdoor:Win32/ZombieRat

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Visual Basic Rat Frameworks

Known Derivatives & Downstream Variants: Zombierat 1.0 · Zombierat 2.0 · Zombierat Gold

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1059.003: Restrict execution of Windows Command Shell (cmd.exe) and block unauthorized batch scripts.
• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
• T1113: Monitor for frequent or unauthorized screen captures or clipboard reads. Restrict background applications from accessing desktop APIs.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5
• 2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4e5f6a7b8c9d0e1f2a3b

Delivery vectors

• Distribution across vintage IRC file sharing channels and P2P networks
• Deceptive email attachments disguised as utility updates or games

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\ZombieRATServer
• %WINDIR%\System32\zombierat_sys.exe

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_ZOMBIERAT_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Zombierat"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "zombierat" ascii wide nocase
        $s2 = "zombierat" ascii wide nocase
        $s3 = "backdoor.win32.zombierat" ascii wide nocase
        $s4 = "zombie rat by the bo$$" ascii wide nocase
        $s5 = "zombierat 1.0" ascii wide nocase
        $s6 = "backdoor:win32/zombierat" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Zombierat (Trojan) Execution & Triage
id: d3732968-9a8e-59cf-8446-2040c369849c
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Zombierat malware family. Detects suspicious execution from temporary user
  directories with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/zombierat
- https://malware-families-catalog.systemhelpdesk.com/defensive/downloader-dropper-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1059_003
- attack.t1547_001
- attack.t1113
- attack.t1083
- attack.t1071_001
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \cscript.exe
    - \wscript.exe
    CommandLine|contains:
    - AppData\Local\Temp
    - -WindowStyle Hidden
    - /e:jscript
    - bitsadmin /transfer
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: medium

rule MALWARE_WIN_ZOMBIERAT_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Zombierat tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "zombierat" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Disconnect the affected host from the local network to sever unauthorized remote administration sessions.
2. Kill the active ZombieRAT server process using Task Manager or administrative tools.
3. Remove startup keys under HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
4. Delete the server binary from the Windows System32 directory.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not execute software attachments received from unknown senders or IRC file exchanges.
2. Avoid exposing Windows workstations directly to the public internet without firewall protection.

References & External Analysis

• Broadcom Symantec Security Response - Backdoor.ZombieRat
• Malware Museum Historical RAT Collection - ZombieRAT
• Search "zombierat" on VirusTotal (External Analysis)
• Search "zombierat" on Any.Run (Sandbox Sandbox)
• Search "zombierat" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Uk_Splitter
• Popad
• Rodecap
• Bindjpg
• Adwind
• Malex
• Xxybvi
• Delphi

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/zombierat.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.