Security Experts:

Flash Player Update Patches Two Critical Vulnerabilities

Adobe has updated Flash Player to version 16.0.0.296 to address a zero-day vulnerability exploited in the wild and a critical security hole that can be leveraged for remote code execution.

Adobe started distributing the update over the weekend via the auto-update mechanism in Flash Player. On Tuesday, the company released a standalone installer.

This out-of-band update was supposed to fix a use-after-free vulnerability (CVE-2015-0311) already exploited by cybercriminals. However, Adobe has also patched a double-free flaw that can be exploited for remote code execution (CVE-2015-0312). CVE-2015-0312 was reported by the researcher using the online moniker “bilou” via the Chromium Vulnerability Rewards Program, but there is no evidence that the bug has been exploited in the wild.

Adobe advises Windows and Mac users to update their Flash Player installations to version 16.0.0.296. The Adobe Flash Player Extended Support Release should be updated to 13.0.0.264. The latest variant of Flash Player for Linux is 11.2.202.440.

With the release of OS X Yosemite 10.10.2, Apple has blocked all Flash Player plugins prior to versions 16.0.0.296 and 13.0.0.264.

CVE-2015-0311 was discovered by French researcher Kafeine while analyzing an instance of the Angler exploit kit. This vulnerability and CVE-2015-0310, which Adobe fixed last week with an emergency patch, have been leveraged by cybercriminals to distribute an ad fraud variant of the Bedep malware.

Initially, CVE-2015-0311 was only seen in the Angler exploit kit, but researchers later discovered that it had also been used in malvertising campaigns targeting adult websites.

“The exploit is being served through advertising banners on adult websites, including one Alexa top 1000 site. The Flash exploit is loaded by plain Javascript generated from php that appears to be devoid of any environmental checks or obfuscations that are typically indicative of the Angler EK,” FireEye researchers noted in a blog post.

Malwarebytes researchers have also analyzed the malvertising campaign affecting a popular adult website and found that the Flash Player exploit has been used to download Bedep. However, Kafeine and FireEye have spotted adult website malvertising attacks in which the exploit has been used to distribute a variant of the notorious Reveton ransomware.

Last week, just before Adobe managed to roll out a patch for CVE-2015-0310, F-Secure noticed that the Angler exploit kit had become the preferred tool of cybercriminals in several regions, including Finland, the United Kingdom and Germany.

As far as CVE-2015-0311 is concerned, Trend Micro believes the exploit has been developed by the same individual or group that created the exploit for CVE-2014-8439, a Flash Player vulnerability patched by Adobe in October 2014.

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.