Security researchers at Adobe Systems claimed that they knew of a Flash bug before it was used to crack a Windows Vista laptop last week in the "PWN To OWN" hacker challenge.
Late Wednesday, Adobe also said it had fixed the flaw and would patch the problem this month.
"After some internal investigation, we found that via our ongoing response and security testing process we were aware of the issue and had fixed it for our security update coming in the next Flash Player update later this month," said Erick Lee, the manager of Adobe's secure software engineering team, in a post to the group's blog.
3Com's TippingPoint, which ponied up the cash prizes awarded for hacking a MacBook Air and the Vista-powered Fujitsu laptop, acquired the vulnerabilities as part of the deal and reported them last week to Apple and Adobe.
At the CanSecWest security conference last Friday, Shane Macaulay of Security Objectives claimed a US$5,000 prize by compromising the Fujitsu using an exploit of the Flash vulnerability Lee said had been known and fixed. According to TippingPoint, Macaulay took several hours to work up an attack, his difficulties caused by some of the defense-in-depth measures added by Microsoft to Service Pack 1 of Vista.
Neither Macaulay nor TippingPoint have discussed the Flash bug in more than general terms.
Lee downplayed the threat posed by the bug Macaulay used. "Adobe is not aware of any active exploits in wild," he said. "The security researchers have reported the information to us responsibly, giving the Flash Player team time to investigate and deliver a patch."
That patch will be issued as part of a previously scheduled update to Flash Player which is to, among other things, fix a long-standing problem posed by .swf files, the Adobe proprietary Shockwave Flash format. The .swf bug, which was reported in December by a Google researcher, has left thousands of Web sites vulnerable to cross-site scripting attacks.
More than three weeks ago, Adobe alerted users that a Flash Player update was coming. Although it said the patches would not affect end users, it warned Web site designers and administrators that they would need to make numerous changes to how they deliver Shockwave Flash content or risk their sites "breaking" when the April update lands on users' desktops.
Adobe was not immediately available to answer questions about when it first knew of the bug and why it had not released it earlier.