Conficker

Overview

Conficker (also known as Downadup or Kido) is one of the most prolific, destructive, and technologically advanced computer worms in internet history, first discovered in November 2008. Conficker propagated autonomously across global networks by exploiting a critical remote code execution vulnerability in the Microsoft Windows Server Service RPC interface (MS08-067 / CVE-2008-4250), requiring no user interaction to infect unpatched machines. At its peak, Conficker compromised an estimated 10 to 15 million computers worldwide, penetrating critical national infrastructure, hospitals, and government and military installations—including the UK Ministry of Defence, the French Navy (Aéronavale), and the German Bundeswehr. The worm employed revolutionary defensive capabilities, including a daily Domain Generation Algorithm (DGA) that queried up to 50,000 domains daily across 116 top-level domains, an encrypted peer-to-peer (P2P) coordination mesh, and ruthless termination of security and antivirus services. In response, Microsoft formed the historic Conficker Working Group and offered a $250,000 bounty for information leading to the arrest of its creators.

Known aliases

Threat reports may refer to this family under multiple names:

• Conficker
• Downadup
• Kido
• Win32/Conficker
• Net-Worm.Win32.Kido

Threat Actor Attribution

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

• Conficker Authors / Conficker Working Group Counter-Operation High confidence
  Basis: Sophisticated Eastern European cybercrime collective. Microsoft established the Conficker Working Group (ICANN, ccTLD registries, major security firms) and posted a $250,000 reward for the identification and capture of the worm's authors. [source]

Family Pedigree & Lineage

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

Known Derivatives & Downstream Variants: Conficker.A (Nov 2008) · Conficker.B (Dec 2008) · Conficker.C (Feb 2009 - 50K Dga) · Conficker.D (Mar 2009 - P2P Mesh) · Conficker.E (Apr 2009)

MITRE ATT&CK Techniques

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

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-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.

• 2b8d0032fecbfde6dc87f7b3dfd2a5f5f4625be25633a9254d39fba0882e85ab
• 378a5e8c1b31a89c89e24e12c1b483f98c4740e2d3d0f01ba3e18a7a2fa2b23a

Delivery vectors

• Autonomous network exploitation of MS08-067 (CVE-2008-4250) over SMB port 445
• Removable USB media propagation using infected autorun.inf scripts
• Brute-force dictionary attacks against Windows administrative SMB shares (ADMIN$)

Persistence mechanisms

• SVCHOST.exe service DLL registration with randomized service name
• Disabling of Windows Update, Windows Defender, BITS, and Error Reporting services

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_CONFICKER_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Conficker"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "conficker" ascii wide nocase
        $s2 = "conficker" ascii wide nocase
        $s3 = "downadup" ascii wide nocase
        $s4 = "kido" ascii wide nocase
        $s5 = "win32/conficker" ascii wide nocase
        $s6 = "net-worm.win32.kido" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Conficker (Worm) Execution & Triage
id: 1255fa65-bf4b-5f30-b7fd-5cc20746bc2c
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Conficker 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/conficker
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-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.worm
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1210
- attack.t1091
- attack.t1562_001
- attack.t1568_002
- attack.t1112
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_CONFICKER_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Conficker 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 = "conficker" 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 the host immediately to prevent Conficker from participating in coordinated Distributed Denial of Service (DDoS) attacks or scanning adjacent network segments.
2. Block outbound IRC, HTTP, or custom command protocols communicating with Conficker command-and-control servers at enterprise perimeter firewalls.
3. Disable AutoRun/AutoPlay and scan removable storage media across the enterprise if Conficker utilizes USB-based propagation vectors.
4. Eradicate rootkit drivers or scheduled task persistence mechanisms used to maintain the Conficker bot agent across reboots.

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 Conficker 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 Conficker 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

• CISA Advisory - Conficker Worm Propagation and Remediation
• NIST NVD - CVE-2008-4250 (MS08-067)
• Conficker Working Group Lessons Learned Report
• CISA Advisory: https://www.cisa.gov/news-events/alerts/2009/03/29/conficker-p2p-worm
• Search "conficker" on VirusTotal (External Analysis)
• Search "conficker" on Any.Run (Sandbox Sandbox)
• Search "conficker" on MalwareBazaar (Malware Samples)

North American Authority Advisory (CISA / NIST)

The Cybersecurity and Infrastructure Security Agency (CISA) has published an official US federal advisory on this family, which can be mapped to NIST Cybersecurity Framework (CSF) incident response controls: https://www.cisa.gov/news-events/alerts/2009/03/29/conficker-p2p-worm ↗

Frequently Asked Questions

Related Threats (Category: Worm)

Explore other documented threats in the same operational category:

• Sytro
• Mofksys
• Mydoom
• Allaple
• Vbs_Worm_Generator
• Blaster
• Lamer
• Chindo

Machine-readable

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