Attackers using two recently-uncovered Java unpatched vulnerabilities, or "zero-days," have quickly expanded their reach by going mainstream, security experts said today.
And on Tuesday, Mozilla, maker of Firefox, joined the chorus of advice that users should disable the current version of Oracle's Java. The company is also ready to automatically block the plug-in from running in its browser, although it has not yet pulled the trigger.
The exploit's breakout followed the addition of attack code to the notorious Blackhole exploit toolkit.
Multiple security firms, including FireEye and Websense, said late Tuesday that the Java exploit had been added to Blackhole, a popular hacker's tool that bundles numerous exploits and tries each in turn until it finds one that will work against a personal computer.
"Exploit code for the Java vulnerabilities has been added to the most prevalent exploit kit out there, Blackhole," said Websense in a short post on its company blog.
The addition of the exploit to Blackhole was cited by FireEye researcher Atif Mushtaq in a similar blog entry yesterday as the basis for a spike in attacks. "After seeing the reliability of this attack, I have no doubt in my mind that within hours the casualties will be in the thousands," said Mushtaq.
Today, Patrik Runald, director of security research at Websense, said his team had found more than 100 unique domains serving the Java exploit.
"The number is definitely growing...and because Blackhole has an updatable framework and already has a foothold on thousands of sites, we anticipate that the number of sites compromised with this new zero-day will escalate rapidly in the coming days," Runald said in an email reply to questions Wednesday.
Initially, the exploit was aimed at a small number of individuals or organizations.
It doesn't appear that the appearance of attack code in Metasploit, the open-source penetration testing framework used by both legitimate researchers and criminals, played a part in the quick dissemination of the exploit. According to Runald, the Blackhole exploit was based on earlier proof-of-concept code.
Yesterday, Michael Coates, Mozilla's director of security assurance, urged Firefox users to disable the browser's Java plug-in because Oracle has not issued fixes. Others, including US-CERT (United States Computer Emergency Readiness Team) have given the same advice, or recommended the more drastic measure of uninstalling Java entirely.