System Installation

The trojan's main file, iexplore.exe, is downloaded via a browser exploit. When run, iexplore.exe drops the following files:

• taskmang.exe
  The trojan's main executable.
• mt_32.dll
  Configuration file containing the command and control server address.

It creates the following service:

• ServiceName = "Taskmng"
  DisplayName = "Windows Task Manager"
  ImagePath = "%System32% askmang.exe"
  

It creates the following registry value:

• [HKEY_CLASSES_ROOTMTBase] = "%System32%mt_32.dll"

The trojan injects itself to the web browser and runs the rest of the code in the context of the browser process.

After the installation, it contacts the server in the control file and starts to wait for commands. The remote server may instruct the trojan to execute any of the following actions:

• Update the trojan's main file
• Remove the trojan from the system
• Download, activate, and remove additional components (plugins)

Plugins

The remote server may instruct the trojan to download additional components using a plugin system. The plugin system consists of DLL files that are loaded by the main trojan or installed to the system using other methods, like browser helper objects (BHO) for Internet Explorer (IE). Plugins communicate with the control server using HTTP requests.

The following DLL files are basic plugins that may be installed to system:

• CertGrabber.dll
  Collects certificates from the system certificate storage.
• ExeLoader.dll
  Executes files.
  
• FFGrabber.dll
  Mozilla FireFox HTTP request sniffer implemented as XML User Interface Language (XUL) extension module.
• IECookieKiller.dll
  Removes cookies from the Internet Explorer cache.
• IEFaker.dll
  Rewrite URLs. The fake addresses are controlled remotely by the attacker, this is reportedly used for phishing.
• IEGrabber.dll
  IE HTTP request sniffer.
• IEMod.dll
  Installs as a BHO and allows other modules to hook on internet connections.
• IEScrGrabber.dll
  Capture IE screenshots.
• IETanGrabber.dll
  Redirects internet connections.
• NetLocker.dll
  Gets/sets a list of system Layered Service Providers (LSP).
• ProxyMod.dll
  Starts HTTP and Socks proxies on a random port.
• PSGrabber.dll
  Collects miscellaneous credientials from the system (email accounts, et cetera).

Other plugins can also be installed to infected system.


Command and Control system

The remote server reportedly hosts a sophisticated command and control system that the attacker can use to control infected systems via a web interface.

Last update 28 March 2007

 

TOP