CyberNew CyberNew
Threat Intelligence & APT BleepingComputer 3 weeks ago

BragJack attacks hijack AI browser agents through malicious extensions

CN
CyberNew Threat Research Desk
• Original Reporting: BleepingComputer
CyberNew Threat Intel Assessment
Assessed Severity: INFORMATIONAL
Impacted Surface
Enterprise Perimeter & Network Defense
Intelligence Sector
Threat Intelligence & APT

Analyst Takeaway

"Security researcher Gal Weizman of Forever Security has disclosed a new attack technique that can hijack the AI assistants built into popular browsers using a single malicious browser extension. Dubbed BragJack, the proof-of-concept was demonstrated against five Chromium-based browsers or browser assistants: Google Chrome's Gemini Live, Perplexity Comet, Microsoft Edge, Opera Neon, and..."

Recommended Defense & Mitigation

  • Threat Monitoring: Ingest published IOCs into SIEM/EDR detection rules for continuous telemetry monitoring.
  • Security Awareness: Alert staff and maintain baseline endpoint hardening across endpoints.
Curated & Verified by CyberNew Threat Intelligence Desk Standard Defense Framework (NIST / MITRE ATT&CK)

browsers

Security researcher Gal Weizman of Forever Security has disclosed a new attack technique that can hijack the AI assistants built into popular browsers using a single malicious browser extension.

Dubbed BragJack, the proof-of-concept was demonstrated against five Chromium-based browsers or browser assistants: Google Chrome's Gemini Live, Perplexity Comet, Microsoft Edge, Opera Neon, and Anthropic's Claude in Chrome.

The research earned more than $20,000 in bug bounties from the five vendors, ranging from $600 to $7,000, and produced two CVEs.

The attack requires the malicious extension to already be installed in the victim's browser.

Once it is, the researcher shows the abuse can run without user interaction, letting an extension control an AI browser agent and abuse its existing privileges to access sensitive information or act on the victim's behalf.

Both Google and Microsoft have since resolved the flaws they were assigned.

Abusing trusted browser components

Save your seat

Source Verification & Original Intelligence

This threat report was reviewed by CyberNew analysts and cross-referenced with primary security disclosures from BleepingComputer.

Primary Advisory →