Meanwhile, hackers used illegitimate "Amazon order" emails to deliver malicious links intended to access personal and financial data, according to Websense. On Sept. 1, the security site intercepted more than 10,000 emails with the subject "You Order With Amazon.com," which urged recipients to click on a hyperlink that sent the victim to a Blackhole exploit kit hacking tool.
"This email campaign further illustrates the ingenuity and speed at which cyber-criminals package and propagate malicious content along with social-engineering techniques in order to exploit both recent software vulnerabilities and the trusting nature of end-users," Websense said.
Oracle released an out-of-band fix last week, but didn't patch the hole entirely. Polish firm Security Explorations said Friday that the update contains a bug that allows hackers to bypass and exploit the system. Security Explorations alerted Oracle to the problem on Friday.
Based on Oracle's four-month update cycle, which rolls around again on Oct. 16, a full fix could be on its way next month. In the meantime, PCMag's lead analyst for security, Neil Rubenking, suggested disabling Java altogether.
Earlier this year, the Flashback Trojan infected more than 550,000 Macs when websites exploited the Java flaw that allows Flashback.K to download itself onto Apple computers without warning.