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.
This vulnerability is the second zero-day vulnerability in Flash to be found in recent days. The first one, identified as CVE-2015-5122, could also be used to take control of affected machines. This was on top of the first Flash zero-day attributed to Hacking Team which was disclosed several days ago and was soon integrated into various exploit kits. A separate Java zero-day (not related to any Hacking Team disclosures) has also been found by Trend Micro researchers.
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:
- From a new BitmapData object, prepare two Array objects, new two MyClass objects, and assign the MyClass object to each Array objects.
- 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.
- 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.
Vulnerability protection in Trend Micro Deep Security protects user systems from threats that may leverage this vulnerability with the following DPI rule:
- 1006859 – Adobe Flash Player BitmapData Remote Code Execution Vulnerability (CVE-2015-5123)
We would like to thank Peleus Uhley of Adobe for helping us in this analysis.
Adobe has released security updates that address critical vulnerabilities, including the one mentioned in this entry, in Adobe Flash Player for Windows, Mac, and Linux. These vulnerabilities could allow attackers to take control of the affected system. The advisory APSB15-18 states that the update addresses affected versions, which include versions 126.96.36.199 and earlier.
Users should update their Adobe Flash as soon as possible. They can verify the version of Adobe Flash Player installed on your system, access the About Flash Player page, or right-click on content running in Flash Player and select About Adobe (or Macromedia) Flash Player from the menu.
Updated on July 12, 2015, 6:48 PM PDT (UTC-7) to add Trend Micro Deep Security solutions.
Updated on July 12, 2015, 11:15 PM PDT (UTC-7) to add links to earlier incidents.
Updated on July 14, 2015, 9:51 AM PDT (UTC-7) to add the Adobe security updates.
Timeline of posts related to the Hacking Team
|July 5||The Italian company Hacking Team was hacked, with more than 400GB of confidential company data made available to the public.|
Three exploits – two for Flash Player and one for the Windows kernel—were initially found in the information dump. One of these [CVE-2015-5119] was a Flash zero-day.
The Windows kernel vulnerability (CVE-2015-2387) existed in the open type font manager module (ATMFD.dll) and can be exploited to bypass the sandbox mitigation mechanism.
|July 11||Two new Flash zero-day vulnerabilities, CVE-2015-5122 and CVE-2015-5123, were found in the hacking team dump.|
|July 13||Further analysis of the hacking team dump revealed that the company used UEFI BIOS rootkit to keep their Remote Control System (RCS) agent installed in their targets’ systems.|
|July 14||A new zero-day vulnerability (CVE-2015-2425) was found in Internet Explorer.|
|July 16||On the mobile front, a fake news app designed to bypass Google Play was discovered.|
|July 20||A new zero-day vulnerability (CVE-2015-2426) was found in Windows, which Microsoft fixed in an out-of-band patch.|
|July 21||Analysis of the RCSAndroid spying tool revealed that Hacking Team can listen to calls and roots devices to get in.|
|July 28||A recent campaign compromised Taiwan and Hong Kong sites to deliver Flash exploits related to Hacking Team.|