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Trojan-Spy:W32/Nuklus.A
Summary
Trojan-Spy:W32/Nuklus.A is a modular malware application mainly used for stealing online bank credentials.
It is installed to the system using a browser exploit. According to published reports, the links to sites containing the exploits were spammed.
It is installed to the system using a browser exploit. According to published reports, the links to sites containing the exploits were spammed.
Disinfection
Automatic Disinfection
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Additional Details
System Installation
The trojan's main file, iexplore.exe, is downloaded via a browser exploit. When run, iexplore.exe drops the following files:
It creates the following service:
It creates the following registry value:
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:
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:
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.
[FSAV_Database_Version]
Version = 2007-02-11_01.
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%\taskmang.exe"
It creates the following registry value:
- [HKEY_CLASSES_ROOT\MTBase] = "%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.
Detection
F-Secure Anti-Virus detects this malware with the following updates:[FSAV_Database_Version]
Version = 2007-02-11_01.