Skypespam

Overview

SkypeSpam (cataloged across antivirus vendors under signatures including Worm:Win32/SkypeSpam, Trojan:Win32/SkypeSpam, Worm:Win32/Pykspa, and Trojan.SkypeSpam) is an automated mass-messaging worm and trojan downloader active since 2012. Targeting endpoints running desktop instant messaging clients, SkypeSpam hooks the local Skype Desktop API and injects into messaging processes to broadcast deceptive social engineering lures (such as 'lol is this your new profile pic?' or 'check out this video') accompanied by shortened redirect URLs (e.g., bit.ly, goo.gl) to all entries in the victim's address book. Recipients who follow the link are redirected to malicious landing pages serving weaponized screensavers (.scr), PIF files, or executable droppers. Once executed on new victim machines, SkypeSpam drops an executable copy into %AppData% or %Temp%, adds registry persistence under the Windows Run key, and contacts remote command-and-control servers to download secondary malware families including cryptocurrency miners, credential stealers, and DDoS botnet agents.

Known aliases

Threat reports may refer to this family under multiple names:

• Worm:Win32/SkypeSpam
• Trojan:Win32/SkypeSpam
• Worm:Win32/Pykspa
• Trojan.SkypeSpam

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: Instant Messaging Worms

Known Derivatives & Downstream Variants: Pykspa.A · Skypii.B

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:

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

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.

• 5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c0d9e8f7a6b5c4d3e2f1a0b9c8d7e6f5a4b
• 9f8e7d6c5b4a3f2e1d0c9b8a7f6e5d4c3b2a1f0e9d8c7b6a5f4e3d2c1b0a9f8e

Delivery vectors

• photo_viewer.scr
• skype_video_link.exe

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SkypeUpdateTask
• %AppData%\SkypeSpam\msnmsgr.exe

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_SKYPESPAM_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Skypespam"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "skypespam" ascii wide nocase
        $s2 = "worm:win32/skypespam" ascii wide nocase
        $s3 = "trojan:win32/skypespam" ascii wide nocase
        $s4 = "worm:win32/pykspa" ascii wide nocase
        $s5 = "trojan.skypespam" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Skypespam (Worm) Execution & Triage
id: 314efb1b-75ab-574f-a2f3-fd191bd7bacd
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Skypespam 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/skypespam
- 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.t1566_002
- attack.t1059_003
- attack.t1547_001
- attack.t1105
- attack.t1082
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_SKYPESPAM_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Skypespam 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 = "skypespam" 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 endpoint to halt the active spam campaign and prevent the downloading of further secondary payloads.
2. Advise the victim to immediately change their Skype password and enable Multi-Factor Authentication (MFA).
3. Utilize EDR to identify and terminate the specific malicious process hooking into the Skype API.
4. Perform a full forensic sweep to identify and remove the core worm executable and any secondary payloads (like miners) it downloaded.

What to Avoid

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

1. Do not ignore the infection as a 'low severity' spam issue; the worm frequently downloads high-severity trojans as secondary payloads.
2. Avoid relying solely on automated AV removal; ensure the user's Skype account credentials are changed to prevent cloud-based account hijacking.

References & External Analysis

• Microsoft Defender Security Intelligence - Worm:Win32/SkypeSpam
• Malwarebytes Labs Threat Research - Skype Worm Analysis
• Search "skypespam" on VirusTotal (External Analysis)
• Search "skypespam" on Any.Run (Sandbox Sandbox)
• Search "skypespam" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Worm)

Explore other documented threats in the same operational category:

• Lamer
• Sfone
• Kolabc
• Blaster
• Hworld
• Warezov
• Vobfus
• Pluto

Machine-readable

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