Gtbot

Overview

Executive Summary

Infection Vector and Technical Capabilities

• IRC Command and Control: The bot quietly connects to a hardcoded IRC server and joins a specific, often password-protected, channel. The "botmaster" controls the entire infected swarm by typing commands directly into the IRC chat interface.
• DDoS Capabilities: The primary function of GTBot was its robust DDoS engine. Upon command, the botmaster could direct thousands of infected hosts to simultaneously launch TCP SYN floods, UDP floods, or HTTP GET floods against a target, overwhelming its infrastructure.
• Modular Architecture (mIRC Scripting): GTBot is actually built upon a modified, hidden version of the legitimate mIRC chat client. Its malicious functionality is driven by highly customized `mIRC.ini` scripts, allowing the botmaster to easily add new capabilities, such as port scanning, keylogging, or downloading secondary malware.

Threat Assessment

Incident Response and Remediation

• Immediate Network Isolation: The endpoint must be disconnected from the network immediately to sever the IRC C2 connection, halting its participation in DDoS attacks and preventing the botmaster from executing further commands.
• Firewall Egress Analysis: Review corporate firewall logs for anomalous outbound connections to known IRC ports (typically TCP 6667, though attackers often use non-standard ports to evade detection). Block these outbound connections to prevent future botnet communications.
• Complete System Rebuild: Because the botmaster had interactive, command-line control over the endpoint via the IRC backdoor, attempting to clean the system is unreliable. The machine must be wiped to bare metal and re-imaged from a known-good baseline.

Known aliases

Threat reports may refer to this family under multiple names:

• Backdoor.IRC.GTBot
• Trojan.GTBot
• Win32/GTBot

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.
• T1071.002: Monitor network traffic for anomalous application layer protocols like non-standard HTTP/S patterns or unexpected DNS requests.

MITRE D3FEND™ Defensive Countermeasures

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

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_GTBOT_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Gtbot"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "gtbot" ascii wide nocase
        $s2 = "backdoor.irc.gtbot" ascii wide nocase
        $s3 = "trojan.gtbot" ascii wide nocase
        $s4 = "win32/gtbot" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Gtbot (Trojan) Execution & Triage
id: f53a13ac-0e54-5de8-b745-d1a9b0b7952c
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Gtbot 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/gtbot
- 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.t1071_002
- attack.t1498_001
- attack.t1059_003
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_GTBOT_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Gtbot 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 = "gtbot" 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. Sever network connectivity for the flagged endpoint to terminate persistent command-and-control (C2) communication channels and stop Gtbot from retrieving secondary stage payloads.
2. Capture process memory triage to detect and terminate malicious threads injected by Gtbot into legitimate system processes such as explorer.exe or svchost.exe.
3. Audit Windows Registry Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run) and Task Scheduler entries to locate and purge Gtbot persistence hooks.
4. Deploy updated enterprise EDR detection signatures and conduct an out-of-band endpoint scan to isolate dropped binaries and staged payloads.
5. Rotate all credentials, domain user passwords, and session cookies active on the system during the Gtbot execution timeframe.

What to Avoid

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

1. Do not assume the incident is resolved simply because an antivirus tool removed the initial Gtbot dropper; always verify that secondary payloads and persistence hooks have been eradicated.
2. Avoid logging in with Domain Admin or privileged credentials on a machine suspected of running Gtbot until memory triage is complete.
3. Do not delay host isolation; automated lateral movement and credential dumping can occur within minutes of initial execution.

References & External Analysis

• Search "gtbot" on VirusTotal (External Analysis)
• Search "gtbot" on Any.Run (Sandbox Sandbox)
• Search "gtbot" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Trash
• Xxybwe
• Vindor
• Lockpos
• Malex
• Winreg
• Indigorose
• Wintrim

Machine-readable

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