Upon execution, the following are the changes made to the system:

File System Changes

It creates these files below:

• %windir%disnisa.exe
• %windir%disnisa.config

Registry Modifications

It sets the values below:

* HKLUSoftwareMicrosoftWindowsCurrentVersionRun
disnisa = C:WINDOWSdisnisa.exe
* HKLMSystemCurrentControlSetServicesW32TimeParameters
NtpServer = time.windows.com,time.nist.gov
* HKLMSystemCurrentControlSetServicesW32TimeParameters
Type = NTP
* HKLMSoftwareMicrosoftTracingFWCFG
EnableFileTracing = 00000000
* HKLMSoftwareMicrosoftTracingFWCFG
EnableConsoleTracing = 00000000
* HKLMSoftwareMicrosoftTracingFWCFG
FileTracingMask = FFFF0000
* HKLMSoftwareMicrosoftTracingFWCFG
ConsoleTracingMask = FFFF0000
* HKLMSoftwareMicrosoftTracingFWCFG
MaxFileSize = 00100000
* HKLMSoftwareMicrosoftTracingFWCFG
FileDirectory = %windir% racing
*HKLMSYSTEMCurrentControlSetServicesSharedAccessParametersFirewallPolicyStandardProfileAuthorizedApplicationsList
C:WINDOWSdisnisa.exe = C:WINDOWSdisinia.exe:*:Enabled:enable

A text file (disnisa.config) is also dropped which contains a possible lists of clients for the worm's peer-to-peer network. The details for the peer names and access ports are encoded.

Another noticeable characteristic for this malware is that it tries to connect to a good number of predefined IP addresses using User Datagram Protocol (UDP).

Furthermore, the files that are detected as Packed.Win32.Tibs.gu are usually downloaded as the result of clicking links from heavily spammed e-mails and websites.

Last update 28 December 2007

 

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