On April 2, security researcher @Kafeine at Proofpoint discovered a change to the Magnitude Exploit Kit. Thanks to their collaboration, we analyzed the sample and discovered that Magnitude EK was exploiting a previously unknown vulnerability in Adobe Flash Player (CVE-2016-1019). The in-the-wild exploit achieves remote code execution on recent versions of Flash Player, but fails on the latest version (21.0.0.197).

While version 21.0.0.197 is vulnerable to this exploit, execution fails because Adobe introduced new exploit mitigations in version 21.0.0.182 of Flash Player. This was a great move from Adobe that shows how valuable innovations into exploit mitigations can be. Before the exploit kit authors could devise a way around the new mitigations, Adobe patched the underlying vulnerability.

Exploit Delivery Chain



Magnitude EK recently updated its delivery chain. It added a profile gate, just like Angler EK, which collects the screen’s dimensions and color depth (Figure 1).

Figure 1. JS of Profile Gate

The server responds with another profiling page, which tries to avoid sending exploits to users browsing from virtual machines or with certain antivirus programs installed (Figure 2). See the appendix for the full list of checks performed.

Figure 2. JS of redirecting to main exploit page

In our tests, Magnitude EK delivered the JSON double free exploit (CVE-2015-2419) and a small Flash loader that renders the new Flash exploit (Figure 3).

Figure 3. JS of loading exploits

The Flash Exploit

A memory corruption vulnerability exists in an undocumented ASnative API. The exploit causes the flash memory allocator to allocate buffers under the attacker’s control. The attacker can then create a ByteArray of length 0xFFFFFFFF such that it can read and write arbitrary memory, as seen in Figure 4. The exploit’s code layout and some of the functionalities are similar to the leaked HackingTeam exploits, in that it downloads malware from another server and executes it.

Figure 4. ActionScript of Flash exploits

Conclusion

This is not the first time that new exploit mitigation research rendered an in-the-wild zero-day exploit ineffective. Exploit mitigations are an invaluable tool for the industry, and their ongoing development within some of the most widely targeted applications – such as Internet Explorer/Edge and Flash Player – change the game.

Despite regular security updates, attackers continue to target Flash Player, primarily because of its ubiquity and cross-platform reach. If Flash Player is required in your environment, ensure that you update to the latest version, and consider the use of mitigation tools such as EMET from Microsoft.



Click here for the security bulletin issued by Adobe.

Acknowledgements

A huge thank you to @Kafeine, without whom this discovery would not be possible. His diligence continues to keep this industry at pace with exploit kit authors around the world.

Appendix

res://\Program%20Files%20(x86)\Fiddler2\Fiddler.exe/#3/#32512

res://\Program%20Files\Fiddler2\Fiddler.exe/#3/#32512

res://\Program%20Files%20(x86)\VMware\VMware Tools\TPAutoConnSvc.exe/#2/#26567

res://\Program%20Files\VMware\VMware Tools\TPAutoConnSvc.exe/#2/#26567

res://\Program%20Files%20(x86)\VMware\VMware Tools\TPAutoConnSvc.exe/#2/#30996

res://\Program%20Files\VMware\VMware Tools\TPAutoConnSvc.exe/#2/#30996

res://\Program%20Files%20(x86)\Oracle\VirtualBox Guest Additions\uninst.exe/#2/#110

res://\Program%20Files\Oracle\VirtualBox Guest Additions\uninst.exe/#2/#110

res://\Program%20Files%20(x86)\Parallels\Parallels Tools\Applications\setup_nativelook.exe/#2/#204

res://\Program%20Files\Parallels\Parallels Tools\Applications\setup_nativelook.exe/#2/#204

res://\Program%20Files%20(x86)\Malwarebytes Anti-Malware\mbamext.dll/#2/202

res://\Program%20Files\Malwarebytes Anti-Malware\mbamext.dll/#2/202

res://\Program%20Files%20(x86)\Malwarebytes Anti-Malware\unins000.exe/#2/DISKIMAGE

res://\Program%20Files\Malwarebytes Anti-Malware\unins000.exe/#2/DISKIMAGE

res://\Program%20Files%20(x86)\Malwarebytes Anti-Exploit\mbae.exe/#2/200

res://\Program%20Files\Malwarebytes Anti-Exploit\mbae.exe/#2/200

res://\Program%20Files%20(x86)\Malwarebytes Anti-Exploit\mbae.exe/#2/201

res://\Program%20Files\Malwarebytes Anti-Exploit\mbae.exe/#2/201

res://\Program%20Files%20(x86)\Malwarebytes Anti-Exploit\unins000.exe/#2/DISKIMAGE

res://\Program%20Files\Malwarebytes Anti-Exploit\unins000.exe/#2/DISKIMAGE

res://\Program%20Files%20(x86)\Trend Micro\Titanium\TmConfig.dll/#2/#30994

res://\Program%20Files\Trend Micro\Titanium\TmConfig.dll/#2/#30994

res://\Program%20Files%20(x86)\Trend Micro\Titanium\TmSystemChecking.dll/#2/#30994

res://\Program%20Files\Trend Micro\Titanium\TmSystemChecking.dll/#2/#30994

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 6.0 for Windows Workstations\shellex.dll/#2/#102

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 6.0 for Windows Workstations\shellex.dll/#2/#102

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 6.0\shellex.dll/#2/#102

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 6.0\shellex.dll/#2/#102

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 7.0\shellex.dll/#2/#102

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 7.0\shellex.dll/#2/#102

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 2009\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 2009\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 2010\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 2010\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 2011\avzkrnl.dll/#2/BBALL

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 2011\avzkrnl.dll/#2/BBALL

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 2012\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 2012\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 2013\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 2013\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 14.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 14.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 15.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 15.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 15.0.1\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 15.0.1\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 15.0.2\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 15.0.2\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Anti-Virus 16.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Anti-Virus 16.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 6.0\shellex.dll/#2/#102

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 6.0\shellex.dll/#2/#102

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 7.0\shellex.dll/#2/#102

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 7.0\shellex.dll/#2/#102

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 2009\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 2009\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 2010\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 2010\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 2011\avzkrnl.dll/#2/BBALL

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 2011\avzkrnl.dll/#2/BBALL

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 2012\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 2012\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 2013\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 2013\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 14.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 14.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 15.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 15.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 15.0.1\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 15.0.1\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 16.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 16.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Internet Security 15.0.2\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Internet Security 15.0.2\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Total Security 14.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Total Security 14.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Total Security 15.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Total Security 15.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Total Security 15.0.1\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Total Security 15.0.1\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Total Security 15.0.2\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Total Security 15.0.2\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky Total Security 16.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky Total Security 16.0.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky PURE 2.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky PURE 2.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky PURE 3.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky PURE 3.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky CRYSTAL 3.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky CRYSTAL 3.0\x86\mfc42.dll/#2/#26567

res://\Program%20Files%20(x86)\Kaspersky Lab\Kaspersky PURE\mfc42.dll/#2/#26567

res://\Program%20Files\Kaspersky Lab\Kaspersky PURE\mfc42.dll/#2/#26567