Newly-Discovered Java 7 Security Vulnerability Poses Risks to Macs

Just two weeks after Oracle officially took over responsibility for Java on OS X with the launch of Java SE 7 Update 6, a new Java vulnerability has been discovered to pose a significant threat to systems running the software. Krebs on Security highlighted the issue yesterday, noting that it affects all versions of Java 7 on most browsers.

News of the vulnerability (CVE-2012-4681) surfaced late last week in a somewhat sparse blog post by FireEye, which said the exploit seemed to work against the latest version of Java 7, which is version 1.7, Update 6. This morning, researchers Andre’ M. DiMino & Mila Parkour published additional details on the targeted attacks seen so far, confirming that the zero-day affects Java 7 Update 0 through 6, but does not appear to impact Java 6 and below.

Initial reports indicated that the exploit code worked against all versions of Internet Explorer, Firefox and Opera, but did not work against Google Chrome. But according to Rapid 7, there is a Metasploit module in development that successfully deploys this exploit against Chrome (on at least Windows XP).

The report notes that Oracle is moving to a quarterly update cycle for Java, meaning that the next regularly-scheduled update to Java SE 7 is not planned until October, but it is unclear how quickly the company will move to address the issue. In the interim, some security experts are developing an unofficial patch while users are advised to simply disable Java if they do not need it active on their systems.

Computerworld reports that the issue does indeed affect fully-updated Macs running Java 7 on top of OS X Mountain Lion.

David Maynor, CTO of Errata Security, confirmed that the Metasploit exploit -- which was published less than 24 hours after the bug was found -- is effective against Java 7 installed on OS X Mountain Lion.

"This exploit works on OS X if you are running the 1.7 JRE [Java Runtime Environment]," said Maynor in an update to an earlier blog post.

JRE 1.7 includes the most-current version of Java 7, dubbed "Update 6," that was released earlier this month.

Both Safari 6 and Firefox 14 have been found to be vulnerable to the issue on OS X systems.

Apple has of course had its own issues with Java vulnerabilities, most recently with the Flashback malware that was able to infect over 600,000 Macs by taking advantage of an exploit in Java 6 that had already been patched by Oracle for most platforms but not by Apple for OS X. It is due to smaller, previous incidents similar to Flashback that Apple had already been moving to shift responsibility for Java updates to Oracle, a move that is taking place with Java 7. But while Mac users will now receive Java updates simultaneously with users on other platforms, Java remains one of the highest-profile targets for attackers seeking to compromise systems on a broad basis.

Update: CNET noted earlier today that most Mac users are not currently susceptible to the issue, as Java 7 is not installed by default on Macs. The current version of Java installed on Mac remains Java 6 for the time being, so users would have to have manually updated to Java 7 in order for their systems to be vulnerable.