Details emerge about a Chrome PDFium bugfix

Jun 9, 2016 23:05 GMT  ·  By

Google has recently patched a high severity security bug in the Chrome browser that allowed crooks to send malicious code to your browser and take over your entire system.

The issue, tracked by the CVE-2016-1681 identifier, affects the browser's built-in PDF reader called PDFium.

Google patched the issue with the release of Chrome 51.0.2704.63, released on May 25. In the meantime, Chrome released another wave of security updates at the start of June.

Cisco discovered the issue, and Google patched it in six days

Cisco's Aleksandar Nikolic was the researcher that discovered and reported the issue to Google, who even awarded him $3,000 for his efforts.

According to the researcher's account, the issue was discovered six days earlier, on May 19, and Google's team fixed it right away.

Nikolic says that CVE-2016-1681 allowed attackers to embed a JPEG2000 image inside a PDF file, which when opened inside a vulnerable Chrome browser, would have triggered a buffer overflow that enabled the threat actor to run arbitrary code on the victim's machine.

Vulnerability was in the OpenJPEG library

The actual vulnerability was not in Chrome or PDFium, but in the OpenJPEG library that parses JPEG2000 files before being displayed inside the browser.

PDF files are so prevalent nowadays that few people think twice before opening one, either locally or on the Web. All of today's major browsers have a PDF reader already built-in, which also helps users think that opening a PDF might be safe.

"The most effective attack vector is for the threat actor to place a malicious PDF file on a website and then redirect victims to the website using either phishing emails or even malvertising," Cisco's Earl Carter wrote today in a technical write-up.

To stay safe, users should update to Google Chrome 51.0.2704.63 or higher. You can do this with the help of the built-in Chrome updater, or you can install a fresh copy of Chrome on top of your existing installation. You can get Google Chrome via Softpedia's download mirrors for Linux, Mac, and Windows users.