New Zero-Day Vulnerability (CVE-2015-5123) in Adobe Flash Emerges from Hacking Team Leak

After two Adobe Flash player zero-days disclosed in a row from the leaked data of Hacking Team, we discovered another Adobe Flash Player zero-day (assigned with CVE number, CVE-2015-5123) that surfaced from the said leak. Adobe has already released a security advisory after we reported the said zero-day. This vulnerability is rated as critical and can allow an attacker to take control of the affected system once successfully exploited.  It affects all versions of Adobe Flash in Windows, Mac, and Linux.

Root cause analysis

Based on our analysis, this vulnerability is also of valueOf trick bug. However, compared to the first two reported Flash zero-day exploits, it involves the BitmapData object and not the TextLine and ByteArray.

The vulnerability can be triggered by the following steps:

1. From a new BitmapData object, prepare two Array objects, new two MyClass objects, and assign the MyClass object to each Array objects.
2. Once the valueOf function of MyClass is override, it calls the BitmapData.paletteMap with the two Array objects as parameters. The BitmapData.paletteMap will trigger the valueOf function.
3. In the valueOf function, it will call BitmapData.dispose() to dispose the underlying memory of BitmapData object, thus causing Flash Player to crash.

We are currently monitoring this proof-of-concept (POC) for any active attacks that may employ this zero-day exploit. We will update this entry as new information and findings surface. Considering that the Hacking team leak is publicly available already, it poses risks to users. As such, we recommend users to disable Adobe Flash Player for the meantime until the patch from Adobe becomes available.

Trend Micro users are proactively protected against this threat via our Sandbox with Script Analyzer engine, which is part of Trend Micro™ Deep Discovery. It can detect this threat via its behavior without any necessary updates. In addition, the Browser Exploit Prevention feature in the Endpoint Security in Trend Micro™ Smart Protection Suite detects the exploit once the user accesses the URL where the exploit is hosted. This security feature can detect exploits targeting browsers or related plugins.

We would like to thank Peleus Uhley of Adobe for helping us in this analysis.

Posts related to vulnerabilities found in the Hacking Team leak:

• Another Zero-Day Vulnerability Arises from Hacking Team Data Leak
• Hacking Team Flash Zero-Day Integrated Into Exploit Kits
• A Look at the Open Type Font Manager Vulnerability from the Hacking Team Leak
• Unpatched Flash Player Flaw, More POCs Found in Hacking Team Leak
• Hacking Team Flash Zero-Day Tied To Attacks In Korea and Japan… on July 1

Post from: Trendlabs Security Intelligence Blog – by Trend Micro

New Zero-Day Vulnerability (CVE-2015-5123) in Adobe Flash Emerges from Hacking Team Leak

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