Cybersecurity researchers from Guardio Labs have revealed a now-patched security flaw in the Opera web browser for Microsoft Windows and Apple macOS, allowing for remote code execution. Codenamed MyFlaw, the vulnerability exploited the My Flow feature, enabling syncing of messages and files between mobile and desktop devices. By using a controlled browser extension, the flaw bypassed the browser’s sandbox and process, impacting both Opera and Opera GX browsers. The issue was responsibly disclosed on November 17, 2023, and subsequently addressed in updates released on November 22, 2023, highlighting the complexities of browser-based attacks and the need for internal design changes.
The MyFlaw vulnerability in Opera took advantage of the My Flow feature, which allows syncing messages and files between mobile and desktop devices. The flaw utilized a controlled browser extension to bypass the browser’s sandbox and process, creating a potential security risk. The flaw impacted both Opera and Opera GX browsers, prompting responsible disclosure on November 17, 2023, and subsequent updates on November 22, 2023, to address the vulnerability. My Flow, featuring a chat-like interface for exchanging notes and files, facilitated file execution outside the browser’s security boundaries, raising concerns about the security of browser extensions.
Guardio Labs, responsible for uncovering the MyFlaw vulnerability, discovered a “long-forgotten” version of the My Flow landing page, indicating a potential avenue for exploitation. This version, hosted on the domain “web.flow.opera.com,” lacked essential security measures, making it vulnerable to code injection. The attack chain involved crafting a specially designed extension masquerading as a mobile device to pair with the victim’s computer. The attacker then transmitted an encrypted malicious payload via a modified JavaScript file, prompting the user to click anywhere on the screen for subsequent execution. The findings underscore the need for internal design changes in browsers and improvements in Chromium’s infrastructure.
Opera responded promptly to close the security hole, implementing a fix on the server side to prevent similar issues in the future. The company emphasized its commitment to maintaining and improving product security, thanking Guardio Labs for their collaboration in uncovering and addressing the vulnerability. The incident highlights the ongoing challenges in ensuring browser security, with suggestions for changes in browser design and infrastructure to mitigate potential risks associated with extensions operating in sandboxed environments.
