Second Java zero-day found: Time to disable it, say experts

Researchers have found a second zero-day Java vulnerability that attackers are using to hijack computers on the web.

An analysis of exploit code found shortly after the first Java flaw was discovered Sunday revealed the second vulnerability. The code has been tied to attackers in China.

“The beauty of this bug class is that it provides 100% reliability and is multiplatform,” Esteban Guillardoy, a developer at Immunity, said Tuesday in announcing the discovery of the second bug. “Hence this will shortly become the penetration test Swiss knife for the next couple of years.”

Users of Java, which is installed in billions of devices worldwide, are notorious for not staying up to date with patches. Rapid7 estimates that 65% of the installations today are unpatched. However, this time around, people with the latest version of Java were the ones most open to attack.

The bugs are in Java 7 and affect Windows, Mac OS X and Linux operating systems running a Web browser with a Java plugin enabled. The flaws were introduced with the release the platform in July 28, 2011, Guillardoy said in his analysis.

Java steward Oracle has not released a fix for either vulnerability. The company has registered the first flaw as CVE-2012-4681 on the Common Vulnerabilities and Exposures list. Joshua Drake, a security researcher from Accuvant, discovered the initial bug.

[See also: Vulnerability management – The basics]

Researchers are advising computer owners to disable Java in all browsers. “That would be the only solution, right now,” said Tod Beardsley, a bug testing engineering manager for Rapid7.

For businesses that need to run Java, Beardsley recommends using a white list that prevents employees from visiting anything but trusted websites.

 Both vulnerabilities are being leveraged in the Blackhole exploit kit, a backdoor Trojan kit used by cybercriminals. “Now that Blackhole has it, you should expect to see it in any kind of attack involving Web sites and Web browsers,” Beardsley said.

Blackhole is one of the most common web threats. Security vendor Sophos found the exploit kit used in 28 percent of the web threats the company detected between October 2011 and March 2012.

The flaws allow a remote attacker to execute code via a Java applet launched by a victim clicking on a link on a hacker’s website or on a hijacked site.

“The applet can run with the same permissions that the user would normally have, so it’s out of the Java sandbox,” Beardsley said. “It can do anything that you can do with your computer. It can upload documents, install keyloggers and backdoors — basically anything.”

Hackers are increasingly targeting Java because it runs on any operating system, which greatly expands the number of available targets. Many of today’s web exploit toolkits rely heavily on Java exploits, which have surpassed Flash Player and Adobe Reader flaws in popularity, experts say.