Kelihos

Overview

Worm:Win32/Kelihos (also known as Hlux) was a massive, highly resilient peer-to-peer (P2P) botnet that operated from 2010 until its final federal dismantling in April 2017. Derived architecturally from the Waledac and Storm Worm codebases, Kelihos comprised a decentralized mesh of more than 100,000 compromised personal computers globally. The botnet was operated as an illicit crimeware infrastructure-as-a-service by Russian cybercriminal Peter Yuryevich Levashov (known online as 'Severa' and 'Peter Severa'). Levashov rented out Kelihos' computational power on underground cybercrime forums to execute pump-and-dump penny stock manipulation campaigns, pump hundreds of millions of illicit pharmaceutical spam emails daily, steal online banking and Bitcoin cryptocurrency wallet credentials, and harvest sensitive email contact lists. Kelihos employed a multi-tier P2P communication protocol where worker bots connected to controller nodes via encrypted TCP port 80 and 443 channels, evading centralized domain sinkholing. In April 2017, Spanish National Police arrested Levashov in Barcelona pursuant to a US international red notice. Extradited to the District of Connecticut, Levashov pleaded guilty in federal court to multiple counts of wire fraud, bank fraud, and CFAA computer offenses, while the FBI and Department of Justice executed court-authorized civil warrants to seize and sinkhole the remaining P2P command infrastructure.

Known aliases

Threat reports may refer to this family under multiple names:

• Kelihos
• Hlux
• Worm:Win32/Kelihos
• Bagle.Kelihos
• Trojan.Kelihos

Threat Actor Attribution

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

• Peter Yuryevich Levashov (Severa) High confidence
  Basis:
• Russian Cybercrime Underground 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: Waledac · Storm Worm

Known Derivatives & Downstream Variants: Kelihos V1 (2010) · Kelihos V2 (2012 P2P Mesh) · Kelihos V3 (2013-2017)

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.
• T1566.002: Inspect email links for known malicious domains and use link-rewriting services for time-of-click analysis.

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-2010-1885 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).
• CVE-2012-0158 — 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.

• 2f82ba1851b415a782bca8ca2107455cf6433ae6506fbc3b53f0fa752243d467
• 7c58ab7df0c8f5379b1836171a4f00843657b8599426f8d0ab7cfeb702221b6c

Delivery vectors

• spam_email_dropper
• drive_by_compromise

Persistence mechanisms

• HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
• Windows Service Creation

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_KELIHOS_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Kelihos"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "kelihos" ascii wide nocase
        $s2 = "kelihos" ascii wide nocase
        $s3 = "hlux" ascii wide nocase
        $s4 = "worm:win32/kelihos" ascii wide nocase
        $s5 = "bagle.kelihos" ascii wide nocase
        $s6 = "trojan.kelihos" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Kelihos (Spam Bot) Execution & Triage
id: 7bdc175a-b9f1-5141-a955-2d3eb37a369f
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Kelihos 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/kelihos
- 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.spam-bot
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1566_002
- attack.t1114_001
- attack.t1005
- attack.t1071_001
- attack.t1560_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_KELIHOS_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Kelihos 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 = "kelihos" 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 infected bot hosts and scan with updated endpoint anti-malware signatures.
2. Block outbound SMTP (port 25) traffic originating from non-mailserver workstations to curb spam propagation.
3. Sinkhole communication to known Kelihos P2P controller nodes and IP subnets.
4. Reset credentials for all email and banking accounts accessed from infected endpoints.

What to Avoid

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

1. Do not allow direct outbound port 25 traffic from general employee workstations.
2. Avoid clicking hyperlinks in unsolicited promotional or stock-recommendation emails.
3. Do not store unencrypted cryptocurrency private keys or seed phrases in plain text files.

References & External Analysis

• US Department of Justice: Russian National Peter Levashov Indicted in Kelihos Botnet Operation
• FBI Cyber Division: Operation Kelihos Takedown
• NIST National Vulnerability Database CVE-2012-0158
• Search "kelihos" on VirusTotal (External Analysis)
• Search "kelihos" on Any.Run (Sandbox Sandbox)
• Search "kelihos" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Spam Bot)

Explore other documented threats in the same operational category:

• Lethic
• Necurs
• Tofsee

Machine-readable

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