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

File System Changes

It creates the following files:

• %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 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 31 December 2007

 

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