Win32/Gimmiv is a trojan that gathers system information from the host computer on which it is installed. The trojan may delete itself after performing its data gathering routine. It consists of two components, TrojanSpy:Win32/Gimmiv.A and TrojanSpy:Win32/Gimmiv.A.dll.
Installation
Win32/Gimmiv may be installed onto an affected system through the successful exploitation of the vulnerability discussed in
Security Bulletin MS08-067. This exploit is detected as
Exploit:Win32/MS08067.gen!A. In the wild, we have observed Win32/Gimmiv being distributed from a remote site as an executable with the file name 'n2.exe'.
Win32/Gimmiv drops a DLL as '<
system folder>\wbem\sysmgr.dll' (detected as '
TrojanSpy:Win32/Gimmiv.A.dll'). The dropped DLL is registered to run as a service. After registering the service, TrojanSpy:Win32/Gimmiv.A drops and runs a batch script that deletes the original Win32/Gimmiv.A executable and then itself.
Payload
Collects System Information
While the service is running, it collects information about the computer in 10 minute intervals. The trojan gathers the following types of information:
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User Name
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Computer Name
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Network Adapters / IP Addresses
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Installed com objects
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Installed programs
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Installed patches
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Recently opened documents
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Outlook Express credentials
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MSN Messenger credentials
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Protected Storage credentials
The trojan then builds a large string containing gathered information and encrypts it. The trojan also creates a cookie named 'ac' that contains particular data.
Connects to Remote Host
The trojan generates a URL based on the operating system and antivirus information, in the following format:
<remote IP address>/test2.php?abc=<abc value>?def=<def value>
Example:
<remote IP address>/test2.php?abc=1?def=2
In the above, <abc value> is numeric and represents an associated type of antivirus application. The value for <def value> is also numeric and defines the operating system. The two values vary depending on the host computer.
The trojan issues a GET request to the constructed URL. The trojan also sends the cookie data to the remote server. At the time of this writing, no further code was downloaded.
Additional Information
As soon as the service finishes gathering information and contacting the remote web site, the trojan service stops, then drops and runs a batch script that unregisters the trojan service and deletes it.
Analysis by Aaron Putnam & Dan Kurc
