Critical Java zero-day bug is being “massively exploited in the wild” (Updated)

A previously unknown and currently unpatched security hole in the latest version of the Java software framework is under attack online, according to security researchers and bloggers.

Attack code that exploits vulnerability in Java's browser plugin has been added to the Blackhole, Cool, Nuclear Pack, and Redkit exploit kits, according to the Malware Don't Need Coffee blog, prompting its author to say that the bug is being "massively exploited in the wild." Miscreants use these products to turn compromised websites into platforms for silently installing keyloggers and other types of malicious software on the computers of unsuspecting visitors. KrebsOnSecurity reporter Brian Krebs said the curators of both Blackhole and Nuclear Pack have taken to the underweb to boast of the addition to their wares. It's not yet clear how many websites have been outfitted with the exploits.

According to researchers at Alienvault Labs, the exploits work against fully patched installations of Java. Attack files are highly obfuscated and are most likely succeeding by bypassing security checks built in to the program. KrebsOnSecurity said the malware authors say the exploits work against all versions of Java 7.