This threat involves malicious browser extensions targeting Chromium-based browsers, masquerading as legitimate AI assistant tools to harvest sensitive data. These extensions have been installed nearly 900,000 times, affecting over 20,000 enterprise tenants globally. The extensions collect comprehensive browsing data, including full URLs visited and chat histories from AI platforms such as ChatGPT and DeepSeek. The attack lifecycle begins with reconnaissance to identify targets, followed by weaponization of the extensions to appear legitimate. Delivery occurs through trusted app stores, leveraging user trust to facilitate installation. Once installed, the extensions maintain persistence within the browser environment and continuously exfiltrate collected data to attacker-controlled infrastructure. This covert data collection transforms a seemingly benign productivity enhancement into a persistent espionage tool embedded in daily enterprise browser usage. The threat leverages multiple MITRE ATT&CK techniques, including data from local system sources, command execution, persistence mechanisms, data staging, and exfiltration over command and control channels. Indicators of compromise include domains such as chatgptsidebar.pro, chatsaigpt.com, deepaichats.com, and chataigpt.pro. No CVE or known exploit in the wild is reported yet, but the scale of installations and enterprise impact is significant. The threat is classified as medium severity due to the potential confidentiality impact and ease of exploitation via social engineering and trusted delivery channels.

The primary impact is the unauthorized disclosure of sensitive organizational information, including confidential AI chat content and detailed browsing histories. This can lead to intellectual property theft, exposure of strategic plans, and leakage of personally identifiable information (PII). Enterprises relying on AI assistants for sensitive tasks are particularly vulnerable, as the stolen chat histories may contain proprietary or confidential data. The persistence of these extensions means long-term data leakage without immediate detection. The widespread installation scale increases the risk of large-scale data breaches affecting thousands of organizations. Additionally, the presence of such malicious extensions undermines trust in browser extension ecosystems and AI productivity tools. The data exfiltration to attacker-controlled domains could facilitate further targeted attacks, espionage, or blackmail. Operational disruption is possible if organizations respond by disabling extensions or restricting browser functionality. Overall, the threat compromises confidentiality and integrity of enterprise data with moderate impact on availability.

1. Implement strict extension management policies in enterprise environments, allowing installation only from verified publishers and trusted sources. 2. Employ browser security tools that can detect and block suspicious extensions and monitor extension permissions regularly. 3. Conduct regular audits of installed browser extensions across all enterprise endpoints to identify and remove unauthorized or suspicious extensions. 4. Monitor network traffic for connections to known malicious domains such as chatgptsidebar.pro, chatsaigpt.com, deepaichats.com, and chataigpt.pro, and block these at the firewall or proxy level. 5. Educate users about the risks of installing unverified AI assistant extensions and encourage verification of extension authenticity before installation. 6. Use endpoint detection and response (EDR) solutions to detect anomalous data exfiltration behaviors associated with browser extensions. 7. Collaborate with browser vendors to report malicious extensions and expedite their removal from app stores. 8. Limit the scope of sensitive data shared with AI assistants and avoid using browser extensions for critical or confidential workflows where possible. 9. Implement data loss prevention (DLP) solutions that can detect and prevent unauthorized transmission of sensitive data from endpoints. 10. Maintain up-to-date inventories of enterprise software and extensions to quickly respond to emerging threats.