Ircbot

Overview

Backdoor:Win32/Ircbot is a foundational lineage of remote access trojans and botnet agents that utilize Internet Relay Chat (IRC) protocol channels for decentralized command and control. Originating from early 2000s codebase roots—including sdbot, Agobot/Gaobot, and Spybot—Ircbot connects silently to preconfigured IRC servers, joining password-protected channels with randomized pseudonyms to receive batch commands from botmasters. Through standardized chat commands (such as .ddos.syn, .download, and .scan), operators direct large armies of infected systems to launch distributed denial-of-service (DDoS) barrages, worm autonomously through local subnets via historic remote code execution vulnerabilities (such as MS03-026 RPC DCOM and MS04-011 LSASS), capture keystrokes, and download secondary crimeware payloads.

Known aliases

Threat reports may refer to this family under multiple names:

• Ircbot
• Backdoor:Win32/Ircbot
• W32.Ircbot
• Backdoor.IRC.Bot
• Trojan.IRC.Zapchast
• Win32/Ircbot
• IRC-Worm

Threat Actor Attribution

Attribution is probabilistic, not a science. Each link below states its confidence level and the evidence behind it.

• Global Cybercrime Syndicates & Botnet Operators High confidence
  Basis:

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: Sdbot

Known Derivatives & Downstream Variants: Ircbot.A · Ircbot.Zapchast · Ircbot.Worm.Variant

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.
• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

MITRE D3FEND™ Defensive Countermeasures

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

Exploited Vulnerabilities (CVEs)

This malware family is documented weaponizing the following common vulnerabilities and exposures:

• CVE-2003-0352 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).
• CVE-2004-0115 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).
• CVE-2008-4250 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).

Command & Control (C2) and Network Profile

How this family talks to its operators. C2 traffic can often identify a family even when its code and configuration are hard to analyse. Ports and patterns are historical and change between campaigns, so use them as hunting leads rather than block-only rules.

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.

• 3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855a
• 94d82f7189a81123490b8484968471e982340918237490182349182093849182

Delivery vectors

• exploit_worms
• malicious_email_attachments

Persistence mechanisms

• HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
• Windows System Directory Binary Dropping

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_IRCBOT_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Ircbot"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "ircbot" ascii wide nocase
        $s2 = "ircbot" ascii wide nocase
        $s3 = "backdoor:win32/ircbot" ascii wide nocase
        $s4 = "w32.ircbot" ascii wide nocase
        $s5 = "backdoor.irc.bot" ascii wide nocase
        $s6 = "trojan.irc.zapchast" ascii wide nocase
        $s7 = "win32/ircbot" ascii wide nocase
        $s8 = "irc-worm" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Ircbot (Rat) Execution & Triage
id: befe4eb5-293e-524e-9b4e-b3faf5da3a63
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Ircbot 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/ircbot
- 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.t1071_002
- attack.t1498
- attack.t1105
- attack.t1547_001
- attack.t1046
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_IRCBOT_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Ircbot 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 = "ircbot" 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. Block enterprise outbound TCP egress on IRC ports 6667, 6668, and 7000.
2. Inspect system memory for processes establishing persistent raw socket sessions.
3. Apply security updates to resolve legacy network service vulnerabilities including MS04-011 and MS08-067.
4. Audit Windows Run registry keys for unauthorized executable entries pointing to system folders.

What to Avoid

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

1. Do not permit direct egress traffic to public IRC servers from corporate desktop subnets.
2. Avoid leaving unpatched network services exposed on internal subnet interfaces.
3. Never disregard anomalous internal port scanning activity detected on ports 445 or 139.

References & External Analysis

• Microsoft Security Intelligence: Backdoor:Win32/Ircbot Technical Details
• SANS Internet Storm Center: IRC Botnet Architectural Analysis
• NIST National Vulnerability Database CVE-2004-0115
• Search "ircbot" on VirusTotal (External Analysis)
• Search "ircbot" on Any.Run (Sandbox Sandbox)
• Search "ircbot" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Rat)

Explore other documented threats in the same operational category:

• Quasarrat
• Houndhack
• Rebhip
• Bladabindi
• Apocalypse_Rat
• Nuclear_Rat
• Recam
• Quasar

Machine-readable

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