Beast

Overview

Beast is a notorious Remote Access Trojan (RAT) that gained significant popularity in the early 2000s, primarily targeting Windows operating systems (Windows 95 through Windows XP). Written in Delphi, it was known for being one of the first RATs to incorporate an 'injection' method, commonly referred to as reverse connection, which allowed it to bypass basic hardware firewalls and NAT configurations. Beast provided a comprehensive suite of malicious capabilities, including file management, registry editing, webcam capture, and keystroke logging. Its graphical user interface (GUI) was notably user-friendly, which lowered the barrier to entry for novice cybercriminals, often termed 'script kiddies'. The architecture of Beast allowed attackers to compile the server component with various settings, enabling customized deployments that could evade simplistic signature-based detection mechanisms of that era.

Known aliases

Threat reports may refer to this family under multiple names:

• Beast RAT
• Tataye

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: Delphi_Reverse_Rat_Engine

Known Derivatives & Downstream Variants: Beast_2.06 · Beast_2.07 · Tataye_Rat

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:

• T1056: Monitor for unauthorized keylogging, screen capturing, or web browser API hooking. Deploy EDR to detect API hooking.
• T1059: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.
• T1125: Restrict access to local camera or microphone APIs. Utilize endpoint protection that monitors hardware access.

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.

• 07c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8
• 18d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9

Delivery vectors

• Social engineering file transfers via instant messaging and IRC networks
• Direct endpoint compromise exploiting Windows DCOM RPC buffer overflows (CVE-2003-0352)

Persistence mechanisms

• DLL injection into winlogon.exe and explorer.exe memory spaces
• HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit modification

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_BEAST_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Beast"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "beast" ascii wide nocase
        $s2 = "beast rat" ascii wide nocase
        $s3 = "tataye" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Beast (Rat) Execution & Triage
id: 0fc01043-53ec-538b-9e16-16ae4fb5af41
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Beast malware family. Detects unauthorized persistence creation via Windows
  Registry Run keys, scheduled tasks, and privilege escalation indicative of RAT installations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/beast
- https://malware-families-catalog.systemhelpdesk.com/defensive/backdoor-rat-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.rat
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1090
- attack.t1056
- attack.t1112
- attack.t1125
- attack.t1059
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \reg.exe
    - \schtasks.exe
    - \cmd.exe
    - \powershell.exe
    CommandLine|contains:
    - \CurrentVersion\Run
    - /create /tn
    - bypass -enc
    - net user /add
    - net localgroup administrators
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: high

rule MALWARE_WIN_BEAST_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Beast 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 = "beast" 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. Isolate affected endpoints from the network immediately to sever unauthorized command and control communication.
2. Identify and terminate active Beast binaries and associated parent-child process chains.
3. Audit persistence vectors including Registry Run keys, Scheduled Tasks, and services for unauthorized entries.
4. Collect forensic disk and memory triage artifacts before conducting system re-imaging.

What to Avoid

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

1. Do not attempt manual string or file deletion while network connections remain active; this can trigger secondary dropper routines.
2. Avoid restoring from backups without verifying that the backup snapshot predates initial Beast installation.

References & External Analysis

• F-Secure Threat Description - Backdoor:W32/Beast
• NIST National Vulnerability Database - CVE-2003-0352
• Search "beast" on VirusTotal (External Analysis)
• Search "beast" on Any.Run (Sandbox Sandbox)
• Search "beast" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Rat)

Explore other documented threats in the same operational category:

• Zegost
• Icecold_Reloaded
• Quasarrat
• Plugx
• Houndhack
• Nuclear_Rat
• Bandook
• Immirat

Machine-readable

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