Nyxem
Overview
Executive Summary
Nyxem (widely known as Kama Sutra, Blackmal, or MyWife) is a highly destructive mass-mailing computer worm that gained global infamy in early 2006. It combines aggressive social engineering (often using sexually explicit lures) with a devastating time-bomb payload designed to systematically overwrite and destroy critical user documents on the third day of every month.Infection Vector and Technical Capabilities
Nyxem propagates almost exclusively via email. It arrives with enticing subject lines (e.g., "Miss Lebanon 2006," "Kama Sutra pic," "Fw: true romance") and an attached executable, often disguised with a double extension (e.g., `.doc.exe` or `.pdf.zip`) or a provocative icon. Upon execution, Nyxem performs the following actions:- Mass Mailing and Harvesting: The worm harvests email addresses from the local system (address books, cached web pages) and uses its own SMTP engine to aggressively mail copies of itself to all found contacts.
- Security Software Neutralization: Nyxem actively hunts for and terminates processes related to antivirus software, firewalls, and security monitoring tools, effectively blinding the host.
- The "Time Bomb" Payload (Destructive Data Wiping): The most critical feature of Nyxem is its destructive payload. It checks the system clock. On the 3rd day of every month, it activates a wiper routine that searches for and overwrites files with specific extensions (`.doc`, `.xls`, `.mdb`, `.mde`, `.ppt`, `.pps`, `.zip`, `.rar`, `.pdf`, `.psd`, `.dmp`) with the text "DATA ERROR [47 0F 94 93 F4 K5]."
Threat Assessment
Nyxem is classified as a critical, destructive threat. The "time bomb" payload ensures that if the infection is not caught within a specific window, the organization will suffer catastrophic, unrecoverable data loss across all infected endpoints. The mass-mailing capability also causes severe network congestion.Incident Response and Remediation
- Immediate Isolation and Clock Modification: If an active infection is suspected and it is nearing the 3rd of the month, immediately isolate the endpoint and, if necessary, alter the system clock to prevent the trigger condition from executing while remediation occurs.
- Outbound SMTP Blocking: Block unauthorized outbound Port 25 (SMTP) traffic at the firewall to halt the worm's propagation.
- Targeted Malware Removal: Run comprehensive anti-malware scans (often from a safe, bootable environment since the worm disables local AV). Because Nyxem *overwrites* files rather than encrypting them, recovery of the targeted documents requires restoring from offline, air-gapped backups.
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1566.001 T1485 T1562.001
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1566.001: Scan email attachments for malicious macros, scripts, or suspicious archive files.
Generated Detections (Boilerplate)
These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.
YARA Rule
rule MALWARE_WIN_NYXEM {
meta:
description = "Detects Nyxem (advanced_threat)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "nyxem" ascii wide nocase
$s2 = "w32.nyxem" ascii wide nocase
$s3 = "worm.kamasutra" ascii wide nocase
$s4 = "w32/blackmal" ascii wide nocase
$s5 = "worm:win32/mywife" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Nyxem Activity
id: 86d6b54d5b9a726a7a8e5d3e4da4a97c
status: experimental
description: Detects generic indicators of the nyxem malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*nyxem*"
- "*w32.nyxem*"
- "*worm.kamasutra*"
- "*w32/blackmal*"
- "*worm:win32/mywife*"
condition: selection
level: mediumReferences & External Analysis
- Search "nyxem" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Nyxem Advanced_Threat from Windows?
Manual removal of Nyxem is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Nyxem a virus or a Advanced_Threat?
Nyxem is classified as a Advanced_Threat. Unlike traditional viruses that infect files, modern malware like Nyxem typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Nyxem infection?
Symptoms of Nyxem can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Related Families (Category: advanced_threat)
Explore other malware families in the same category:
Protect Your Network Against Advanced_Threats
Want to prevent Nyxem and similar threats from compromising your organization? Read our comprehensive defensive guide: Suspect an Infection? What to do.
Machine-readable
Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/nyxem.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.