Full Report
ClickFix, FileFix, fake CAPTCHA — whatever you call it, attacks where users interact with malicious scripts in their web browser are a fast-growing source of security breaches. ClickFix attacks prompt the user to solve some kind of problem or challenge in the browser — most commonly a CAPTCHA, but also things like fixing an error on a webpage. The name is a little misleading, though
Analysis Summary
# Tool/Technique: ClickFix Attacks (Copy/Paste Browser Attacks)
## Overview
ClickFix attacks (also referred to as FileFix or fake CAPTCHA attacks) are a sophisticated form of browser-based compromise where attackers trick users into using the clipboard functionality to execute malicious commands locally on their device. These attacks rely on social engineering, often disguised as CAPTCHAs or error-fixing prompts, combined with JavaScript automation to populate the victim's clipboard before instructing the user to paste the contents (e.g., into a command prompt).
## Technical Details
- Type: Technique / Attack Pattern
- Platform: Web Browsers (Targeting user execution environments like Command Prompt, PowerShell, etc., following the copy action)
- Capabilities: Automated clipboard population using JavaScript; disguising malicious instructions as legitimate troubleshooting or verification steps; leveraging non-email delivery vectors.
- First Seen: Based on context, they are noted as a fast-growing source of breaches in late 2025, implying recent popularization, though the underlying browser capabilities enabling this have existed.
## MITRE ATT&CK Mapping
Since ClickFix is a delivery and execution mechanism utilizing social engineering, the mapping focuses on the delivery and initial access:
- **TA0001 - Initial Access**
- T1189 - Drive-by Compromise
- *Note: While not a traditional drive-by, the automatic presentation of the exploit/lure via a compromised website fits this high-level goal.*
- T1566 - Phishing
- T1566.002 - Spearphishing Link (Delivery via search results, malvertising)
- **TA0002 - Execution**
- T1059 - Command and Scripting Interpreter
- T1059.001 - PowerShell
- T1059.003 - Windows Command Shell
- *Note: The technique relies on tricking the user into running commands derived from the clipboard.*
## Functionality
### Core Capabilities
- **Clipboard Manipulation:** Automatic population of the user's system clipboard with malicious commands (often obfuscated) using JavaScript running within the browser context.
- **Social Engineering Lure:** Presenting the victim with a convincing interface (e.g., fake CAPTCHA, error message) that requires user action ("fixing" the page or completing the challenge).
- **User Instruction:** Directing the user to copy the pre-loaded malicious content from the page and paste it into a local terminal or other execution environment.
### Advanced Features
- **Detection Evasion:** Utilizing domain rotation, camouflage, and content obfuscation to bypass web proxies, email scanners, and web-crawling security tools.
- **Non-Email Delivery:** Heavy reliance on **SEO poisoning** and **malvertising** (especially via Google Search results) to reach victims outside traditional email security perimeters.
- **Legitimization:** Modern lures incorporate professional designs and even embedded videos demonstrating the required steps, increasing user trust.
## Indicators of Compromise
*Note: Specific hashes or complete network indicators are not provided in the context article, so this section reflects the indicators related to the *attack pattern* itself.*
- File Hashes: [N/A - Artifacts depend on the payload pasted by the user]
- File Names: [N/A]
- Registry Keys: [N/A]
- Network Indicators:
- Delivery Vectors: Domains compromised via SEO poisoning or legitimate domains hosting malvertising banners.
- Example Domains (Defanged):hxxp://[compromised-site].com or newly registered domains used for hosting the ClickFix lure page.
- Behavioral Indicators:
- User is prompted to solve a browser challenge, but the instructions require copying text disguised as troubleshooting steps.
- Subsequent execution of commands obtained *from system clipboard* immediately following a website visit.
## Associated Threat Actors
- Interlock ransomware group
- State-sponsored APTs
- Other prolific threat actors
## Detection Methods
*Detection focuses on the delivery and the unusual user behavior.*
- Signature-based detection: Difficult due to constant domain rotation and code obfuscation on the lure pages. Detection relies on signatures against known obfuscation patterns or payload hashes after a dump.
- Behavioral detection: Monitoring for scripts that automatically set the clipboard contents when the user has not explicitly initiated a copy action (e.g., keyboard/mouse events correlating with `document.execCommand('copy')` triggers that aren't standard UI interactions).
- YARA rules: Applicable to the retrieved payload once it is successfully copied to the clipboard or executed.
## Mitigation Strategies
- **User Awareness:** Specific training focusing on the danger of copying and pasting instructions from web pages (especially troubleshooting/CAPTCHA pages) into terminal windows. Move awareness beyond just suspicious emails.
- **Technical Controls:** Implementing robust browser security policies and monitoring clipboard usage, especially regarding automated copy events triggered without direct user input.
- **Delivery Vector Defense:** Improving defenses against malvertising and SEO poisoning by rigorously vetting external links delivered via search engines. Enforcing Content Security Policy (CSP) where possible to restrict script execution.
## Related Tools/Techniques
- Traditional Phishing Sites
- Malvertising Campaigns
- Watering Hole Attacks (as part of delivery via SEO poisoning)