Incident Response, TDR, Vulnerability Management

Users still running Java 6 vulnerable to zero-day exploit

A "critical" vulnerability impacting the out-of-date, but still widely used, Java 6 platform has been added to a commercially available exploit kit.

Timo Hirvonen, a senior analyst at security firm F-Secure, told that on Monday he first saw the bug (CVE-2013-2463) exploited in the wild via the Neutrino exploit kit. And although those who've upgraded to the latest Java version, 7u25 released in June, are patched against the threat, users running Java 6 remain vulnerable to attacks.

Oracle, which maintains Java, dispatched its final fix for Java 6 in April, and now only organizations with support contracts have access to updates.

“An attacker can execute their own code on the system to infect it with malware,” Hirvonen said of the exploit. “It might be that you get some links in spam, and that link leads to this Neutrino exploit kit, or you visit an infected website,” and unknowingly install the exploit kit, a process known as drive-by download.

Hirvonen told that the exploit's proof-of-concept was made public last week, prior to in-the-wild attacks surfacing on Monday.

According to Oracle's June critical patch update advisory, the vulnerability was assigned a score of 10 out of 10 on Oracle's implementation of the Common Vulnerability Scoring System, the highest mark. The vulnerability lies in Java Runtime Environment's 2D sub-component, which is used to make two-dimensional graphics.

Wolfgang Kandek, CTO of cloud security firm Qualys, told on Tuesday that the use of Java 6 still is prevalent, opening up a significant number of users to the threat.

After analyzing millions of endpoints throughout May, June and July, the firm found that about half of the users were still running Java 6 installations.

For organizations concerned about disrupting mission-critical applications, if they try to disable or update Java 6, considering many software applications still depend on the version, they should consider whitelisting Java applets through their browsers, a feature supported by Internet Explorer and Google Chrome, Kandek said.

However, the safest option, he advised, is to bite the bullet and upgrade to the patched version of the platform.

“[Java 6] is very widely used, and since it is out of support since April, there's no way to fix this other than to go to the Java 7 version,” Kandek said.

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