Sophos

Troj/Cimuz-O

Aliases
  • Trojan-Proxy.Win32.Cimuz.bz
Category
Type
What to do
Prevalence low high

Summary

 
Affected operating systems Windows
Characteristics
  • Installs itself in the registry
Included in our products from February 2006 (4.02)
Protection available since 10 December 2005 17:10:57 (GMT)
Detected by All Sophos products

Action

More Information

Troj/Cimuz-O is a backdoor Trojan for the Windows platform.

Troj/Cimuz-O includes functionality to access the internet and communicate with a remote server via HTTP.

Troj/Cimuz-O acts as a proxy server, and may download and execute remote files.

When first run Troj/Cimuz-O copies itself to <System>\mdms.exe and creates the following files:

<System>\sporder.dll
<System>\mswsck2.dll

The file mswsck2.dll is detected as Troj/Cimuz-O when dropped correctly, though Troj/Cimuz-O may corrupted the file when it is dropped, turning it into a clean data file. The file sporder.dll appears to be a clean Windows dll.

The following registry entry is created to run mdms.exe on startup:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
SysMemory manager
<System>\mdms.exe

Troj/Cimuz-O attempts to terminate processes, set registry values, and corrupt files related to anti-virus and security programs.

The following registry entry is set, allowing mdms.exe to bypass the Windows firewall:

HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\
Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\
<System>\mdms.exe
<System>\mdms.exe:*:Enabled:mdm_sysag

Troj/Cimuz-O may attempt to stealth its presence from certain processes.

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