XSS Vulnerability Found in Acrobat’s Silently Installed Chrome Extension

Researcher Tavis Ormandy who was a part of Google Project Zero has discovered that a Chrome extension installed by Adobe silently last week had been affected by an XSS(cross-site scripting) vulnerability. After learning of its existence, Adobe quickly patched the flaw.

The Adobe released an update to Adobe reader on January 10 and it was to address 29 vulnerabilities in it. However, some users are not pleased that the updates also automatically installed an Adobe Acrobat Chrome extension which was designed to convert web pages into PDF files.

This extension is available only for Windows. This extension requires the permission to access data on the websites that the user visits, communicate with cooperating native apps and manage downloads. This tool also collects information from the system, but still, Adobe claims no personal information is involved and the “anonymous data will not be meaningful to anyone outside of Adobe.”

After thoroughly analysing this extension, which already has like 30 million installs, Ormandy identified that a DOM-based XSS vulnerability which allowed privileged JavaScript code execution. The experts classified this security hole as a “critical severity.”

“I think CSP [Content Security Policy] might make it impossible to jump straight to script execution, but you can iframe non web_accessible_resources, and easily pivot that to code execution, or change privacy options via options.html, etc,” the Google researcher explained in an advisory.

The issue was reported to Adobe back on January 12 and it was patched a few days after that. It is not surprising that the vulnerability was fixed quickly considering that many of the flaws found in Adobe products are reported by Google Project Zero researchers or through the Chromium Vulnerability Rewards Program.

This was not the first time Ormandy identified a vulnerability in a Chrome extension. Roughly one year ago, the expert revealed that an extension automatically installed by AVG AntiVirus exposed user’s personal data and other browsing histories.

Source : Latest Hacking News