Cridex
Overview
Executive Summary
Cridex is a highly influential banking trojan and worm that emerged in 2011, notorious for being the direct predecessor to the devastating Dridex botnet. Designed for aggressive financial theft, Cridex infected systems to harvest banking credentials, intercept secure web sessions, and rapidly propagate across local networks and removable media, causing massive financial losses in the early 2010s.Infection Vector and Technical Capabilities
Cridex utilized a multi-pronged distribution strategy, primarily leveraging massive spam campaigns containing malicious attachments (often ZIP files containing executable droppers) and drive-by downloads via the Blackhole Exploit Kit. Once active, Cridex combined the espionage capabilities of a banking trojan with the spread of a worm:- Web Injection (Man-in-the-Browser): Cridex's primary weapon was its ability to inject malicious HTML and JavaScript directly into the user's web browser in real-time (MitB). When a victim visited a targeted banking portal, Cridex would alter the login page, requesting additional sensitive information (like ATM PINs or mother's maiden name) and bypassing two-factor authentication.
- Worm Propagation: Unlike modern banking trojans, Cridex actively sought to spread. It monitored the system for newly inserted USB flash drives, copying itself and creating an `AutoRun.inf` file. It also attempted to spread across open SMB network shares using weak or stolen credentials.
- Peer-to-Peer (P2P) Architecture: Later variants of Cridex experimented with a P2P command-and-control (C2) architecture. Instead of relying on a centralized server that could be easily taken down, infected nodes communicated with each other to distribute configuration files and exfiltrate stolen data.
Threat Assessment
A Cridex infection represents a critical security incident resulting in immediate financial risk. The theft of banking credentials combined with the worm's ability to rapidly infect an entire corporate network makes it a highly destructive threat that requires immediate containment.Remediation and Eradication
- Immediate Network Segmentation: Physically or logically segment the infected endpoint and its surrounding VLAN to halt the lateral spread of the worm via SMB shares.
- Credential Reset and Fraud Alert: All financial institutions accessed from the infected machine must be notified immediately. All session tokens and credentials must be revoked and reset.
- Disable AutoRun: Ensure enterprise-wide Group Policy Objects (GPOs) completely disable AutoRun and AutoPlay to prevent the USB propagation vector.
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: T1056.004 T1091 T1185 T1566.001
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1056.004: Monitor for unauthorized keylogging, screen capturing, or web browser API hooking. Deploy EDR to detect API hooking.
- T1185: Enforce strong MFA and use browser isolation or hardened browsers for sensitive financial or administrative portals to defeat session hijacking.
- 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_CRIDEX {
meta:
description = "Detects Cridex (trojan)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "cridex" ascii wide nocase
$s2 = "worm.cridex" ascii wide nocase
$s3 = "trojan.cridex" ascii wide nocase
$s4 = "w32/cridex" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Cridex Activity
id: 6ad9df3c10a5f924ca7200ed91343901
status: experimental
description: Detects generic indicators of the cridex malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*cridex*"
- "*worm.cridex*"
- "*trojan.cridex*"
- "*w32/cridex*"
condition: selection
level: mediumReferences & External Analysis
- Search "cridex" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Cridex Trojan from Windows?
Manual removal of Cridex 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 Cridex a virus or a Trojan?
Cridex is classified as a Trojan. Unlike traditional viruses that infect files, modern malware like Cridex typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Cridex infection?
Symptoms of Cridex 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: trojan)
Explore other malware families in the same category:
Protect Your Network Against Trojans
Want to prevent Cridex and similar threats from compromising your organization? Read our comprehensive defensive guide: Banking Trojan Protection.
Machine-readable
Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/cridex.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.