Threat Descriptions

Packed:W32/Tibs.GU

Classification

Category :

Malware

Type :

Email-Worm

Platform :

W32

Aliases :

Packed:W32/Tibs.GU

Summary

Files that are detected as Packed.Win32.Tibs.gu have similar functionality to Email-Worm.Win32.Zhelatin variants.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

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:

  • HKLU\Software\Microsoft\Windows\CurrentVersion\Run disnisa = C:\WINDOWS\disnisa.exe
  • HKLM\System\CurrentControlSet\Services\W32Time\Parameters NtpServer = time.windows.com,time.nist.gov
  • HKLM\System\CurrentControlSet\Services\W32Time\Parameters Type = NTP
  • HKLM\Software\Microsoft\Tracing\FWCFG EnableFileTracing = 00000000
  • HKLM\Software\Microsoft\Tracing\FWCFG EnableConsoleTracing = 00000000
  • HKLM\Software\Microsoft\Tracing\FWCFG FileTracingMask = FFFF0000
  • HKLM\Software\Microsoft\Tracing\FWCFG ConsoleTracingMask = FFFF0000
  • HKLM\Software\Microsoft\Tracing\FWCFG MaxFileSize = 00100000
  • HKLM\Software\Microsoft\Tracing\FWCFG FileDirectory = %windir%\tracing
  • HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List C:\WINDOWS\disnisa.exe = C:\WINDOWS\disinia.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 emails and websites.