Researchers explained one large security hole in Apple’s iMessage app that received a patch last month, but until now we didn’t have details on another vulnerability fixed at the same time. By tricking users into clicking a specially-crafted link, hackers could gain access to the usually encrypted communications in OS X El Capitan’s Messages. “You don’t need a graduate degree in mathematics to exploit it, nor does it require advanced knowledge of memory management, shellcode or ROP chains,” according to security researchers at Bishop Fox — just knowledge of basic JavaScript.
Simply clicking the nefarious link from a sender grants them access to your plaintext messages and any attachments. That bit of JavaScript could even look like a legitimate link, as you’ll see in the video below. From there the cross-site scripting attack (XSS) is executed and uploads your stuff to a remote server. Flaws like these have usually been common in web browsers, but as the team points out, use of rendering engines like WebKit can bring them to other apps as well.
The team reported the problem (CVE-2016-1764) to Apple before publicly announcing how it works, and the company’s patch fixes things with “improved content security policy checks.” As always, make sure you have all of the latest updates installed, and double check links before blindly clicking on them. Protip: The ones that start with javascript:// probably won’t actually reveal what all of your Facebook friends are secretly saying about you.
[youtube https://www.youtube.com/watch?v=9rgA_xqwWVE?wmode=opaque]
iMessage executes Javascript URLs. What is this clown show. https://t.co/lxuAIutKaO
— Matthew Green (@matthew_d_green) April 8, 2016
Via: Matthew D. Green (Twitter)
Source: Bishop Fox