Adobe has patched new vulnerabilities in Flash Player that hackers are now exploiting in attacks aimed at Firefox users, the company said.
Today's surprise update to Flash Player was the second emergency fix this month, the third overall for February, and the fourth since the start of 2013.
In the accompanying advisory, Adobe confirmed it was patching three vulnerabilities in the popular media player browser plug-in. Two of the trio, said Adobe, are being used by attackers.
"Adobe is aware of reports that CVE-2013-0643 and CVE-2013-0648 are being exploited in the wild in targeted attacks designed to trick the user into clicking a link which directs to a website serving malicious Flash content," the advisory stated, listing the vulnerabilities by their Common Vulnerabilities & Exposures, or CVE, identifiers. "The exploit for CVE-2013-0643 and CVE-2013-0648 is designed to target the Firefox browser."
The two flaws singled out by Adobe are thus "zero-day" vulnerabilities, meaning criminals have exploited them with attack code before the bugs were patched.
Adobe did not credit a researcher for reporting either CVE-2013-0643 or CVE-2013-0648. And Mozilla did not immediately reply to questions about the attacks Adobe said were targeting only Firefox, or whether its security team had spotted the attacks and notified Adobe.
Tuesday's "out-of-band" came less than three weeks after a Feb. 8 fix for two exploited-in-the-wild flaws. Adobe has also issued two other regularly-scheduled updates for Flash this year as part of its plan to synchronize its security releases with Microsoft's monthly Patch Tuesdays.
The frequent Flash updates only add to what has become a hectic start to the year for security experts and IT administrators: Oracle has also shipped multiple updates for Java in the last two months, including a pair of rush updates to quash actively-exploited bugs.
"These past two months have been a whirlwind of advisories from vendors," noted Wolfgang Kandek, CTO of Qualys, in an interview via instant messaging today. "I think many IT shops have [had] a hard time keeping up."
Kandek also noted that it was unusual for a particular browser to be singled out.
In fact, Firefox recently lowered the boom on plug-ins. At the end of January, Mozilla announced it was automatically disabling all plug-ins in Firefox except the latest version of Adobe's Flash Player, saying the drastic step was needed to safeguard users from "drive-by" attacks, which trigger exploits as soon as a victim visits a malicious or compromised website.
The feature, called "click-to-play," bars plug-in play, and has become popular as browser makers try to keep users safe from a rising tide of exploits that leverage bugs in plug-ins.
But because the attacks mentioned by Adobe were exploiting unpatched vulnerabilities in the most-up-to-date Flash Player, Firefox's click-to-play defense, even had it been fully implemented -- according to Mozilla's blacklist, it had not -- would not have protected its users.
The patched versions of Flash Player for Windows, Mac and Linux can be downloaded from Adobe's website. Windows and Mac users can also wait for Flash's automatic updating tool to kick in. Users of Google's Chrome and Microsoft's Internet Explorer 10 (IE10) on Windows 8 will receive the newest Flash via those browsers' own update mechanisms.