Shylock

Overview

Shylock (also cataloged across international law enforcement and intelligence communities as Capito) is a sophisticated financial malware family and banking trojan first observed in 2011. The malware derives its moniker from its code, which contains numerous verbatim quotes and excerpts from William Shakespeare's play *The Merchant of Venice*. Shylock was designed for high-value financial theft, targeting business and consumer online banking accounts across the United Kingdom, the United States, and Europe. Shylock utilized advanced browser man-in-the-browser (MitB) injection techniques, local proxy redirection, and digital certificate manipulation to hijack authenticated banking sessions and execute fraudulent wire transfers. In July 2014, an elite international law enforcement coalition led by the UK National Crime Agency (NCA), Europol's European Cybercrime Centre (EC3), the FBI, Dutch Police, and CERT-EU executed 'Operation Capito'. The operation seized control of Shylock's central command servers and disrupted dozens of its domain generation algorithm (DGA) domains across .cc, .su, and .me registries, neutralizing the botnet's infrastructure.

Known aliases

Threat reports may refer to this family under multiple names:

• Shylock
• Capito
• Trojan.Shylock
• Win32/Shylock
• Banking.Shylock

Threat Actor Attribution

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

• Shylock Cybercrime Syndicate / UK NCA & Europol Operation Capito (July 2014) High confidence
  Basis: International law enforcement coalition led by the UK National Crime Agency (NCA), Europol EC3, the FBI, and CERT-EU executed Operation Capito in July 2014, seizing central command infrastructure and disrupting Shylock globally. [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: Shylock V1.0 · Shylock V2.0 (P2P & Dga Integration) · Shylock Usb Worm Propagation Module

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:

• T1185: Enforce strong MFA and use browser isolation or hardened browsers for sensitive financial or administrative portals to defeat session hijacking.

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-2010-2568 — 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.

• 0f62d1c9ad9a64797a731efc1b4cfb0cc5a1b5d12de1d668749a46995642456e
• 294ac5e533c37560d2b8feeb492f58cfcb6c3c6efec24bb93b22cfd8ccb05612

Delivery vectors

• Malicious email attachments exploiting Microsoft Office (CVE-2012-0158)
• Drive-by downloads from compromised websites hosting exploit kits
• Removable USB drive propagation using CVE-2010-2568 shortcut files

Persistence mechanisms

• Browser injection hooking WinINet and NSS cryptographic libraries
• Service creation and registry Run key installation in %APPDATA%

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_SHYLOCK_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Shylock"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "shylock" ascii wide nocase
        $s2 = "shylock" ascii wide nocase
        $s3 = "capito" ascii wide nocase
        $s4 = "trojan.shylock" ascii wide nocase
        $s5 = "win32/shylock" ascii wide nocase
        $s6 = "banking.shylock" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Shylock (Banking Trojan) Execution & Triage
id: 06403711-d657-58d0-8b7b-b3ee57f678d2
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Shylock malware family. Detects recon staging, certutil file payload staging,
  and web-inject process proxying characteristic of banking trojan initial loaders.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/shylock
- https://malware-families-catalog.systemhelpdesk.com/defensive/banking-trojan-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.banking-trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1055
- attack.t1056_001
- attack.t1113
- attack.t1071_001
- attack.t1568_002
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \svchost.exe
    - \explorer.exe
    - \msiexec.exe
    - \certutil.exe
    CommandLine|contains:
    - -urlcache
    - -split -f
    - ipconfig /all
    - route print
    - netstat -ano
  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_SHYLOCK_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Shylock 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 = "shylock" 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. Instantly isolate the endpoint; the attacker has active, real-time control over the user's web browser sessions.
2. Initiate a mandatory password reset for all financial and corporate accounts accessed from the infected machine, utilizing a known-clean device.
3. Capture a forensic memory image (RAM dump) to extract the decrypted web inject configurations and identify which specific banking portals were targeted.
4. Assume total endpoint compromise; perform a clean OS rebuild and force the revocation of any session tokens or cookies stored on the machine.

What to Avoid

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

1. Do not allow the user to log into any sensitive portal to 'check their balance'; the MitB trojan will intercept the login and modify the displayed balance.
2. Avoid relying solely on basic antivirus scans, as Shylock stores its payload in encrypted Alternate Data Streams (ADS) that evade standard file-level scanning.

References & External Analysis

• Europol Press Release - Operation Capito Targets Shylock Malware
• UK National Crime Agency (NCA) - Shylock Takedown Announcement
• MITRE ATT&CK - Shylock
• Search "shylock" on VirusTotal (External Analysis)
• Search "shylock" on Any.Run (Sandbox Sandbox)
• Search "shylock" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Banking Trojan)

Explore other documented threats in the same operational category:

• Goznym
• Dridex
• Danabot
• Blackmoon
• Carberp
• A_311_Death
• Mekotio
• Trickster

Machine-readable

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