The Dell SonicWALL Threats Research team analyzed a drive by download exploit kit targets Adobe Flash family named GAV: Angler.EK1 which leads to the download of additional malware on the target system upon successful exploit run. Angler exploit kit is known for its use of various Adobe Flash Player exploits, this time the attackers used Adobe Flash Exploits such as CVE-2015-0313.

Infection Cycle:

Md5s:

• GAV: Angler.EKSWF1- SWF Flash Exploit

  • ae4e271b1923c17ef589acba603f2b8a

• GAV: Angler.EKSWF2- SWF Flash Exploit

  • 4334efd4612b1f095b3919485dc66ecd

• GAV: Angler.EK1 – Executable Dropper

  • a29acacfc2b5e44cdbfb769ce9cf9ccf

  • 2e297279f7d919e4e67464af91fb6516

• GAV: Angler.EK2 – Executable Dropper

  • 37cd5cb1ebabcb921fe20341c2a63fc4

• GAV: Angler.EK3 – Executable Dropper

  • f15e26ce666d26ef664c196d7ef3e0ed

The Malware adds the following files to the system:

• Angler.EK1

  • %Userprofile%raxgyxjo.exe

  • %Userprofile%Local SettingsTemp6238.bat

• Angler.EK2 ,3

  • %Userprofile%Local SettingsTempmmc32E964E3.xml [MMC + 8 Random strings].XML

  • %Userprofile%Local SettingsApplication Datakmqglxwyvq.png

The Malware adds the following keys to the Windows registry to ensure persistence upon reboot:

• HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun

  • MSConfig”=””%Userprofile%raxgyxjo.exe

The file raxgyxjo.exe registered as auto startup on windows registry, after next restart the malware uses an injected Svchost.exe to collecting information about the target computer and sending Spam Emails to the new targets.

Once the computer is compromised, the Malware runs the following commands on the system:

Next, the malware generates a Unique ID from your system and save it into a PNG file over here %Userprofile%Local SettingsApplication Data kmqglxwyvq.png

This UID is saved for sending to C&C server, here is an example:

After a while malware tries to spread itself via spams to new targets, the injected Svchost.exe is responsible for that reason, here is an example:

Command and Control (C&C) Traffic

Angler.EK1 performs C&C communication over ports 25, 80 and 4101. The malware sends the UID of your system to its own C&C server via following Http format, here are some examples:

The malware retrieves the random Email addresses from its own C&C Server and starts to sending spams to those email addresses, here an example:

Here is some information about C&C server:

SonicWALL Gateway AntiVirus provides protection against this threat via the following signatures:

• GAV: Angler.EKSWF1

• GAV: Angler.EKSWF2

• GAV: Angler.EK1

• GAV: Angler.EK2

• GAV: Angler.EK3