Sophos

Troj/Oscor-B

Aliases
  • W32/Ginwui.A
  • Backdoor.Ginwui
Category
Type
What to do
Prevalence low high

Summary

 
Affected operating systems Windows
Included in our products from July 2006 (4.07)
Protection available since 19 May 2006 15:09:17 (GMT)
Last updated 20 May 2006 22:29:14 (GMT)
Detected by All Sophos products

Action

More Information

Troj/Oscor-B is a backdoor Trojan which allows a remote intruder to gain access and control over the computer.

Troj/Oscor-B includes functionality to communicate with a remote server via http.

After the computer has been restarted, Troj/Oscor-B attempts to contact http://localhosts.3322.org.

Troj/Oscor-B includes a stealthing functionality. It hides:

The process
The file <system>\winguis.dll
The data in the registry entry

When first run Troj/Oscor-B copies itself to <Temp>\20060424.bak, deletes the original sample and creates the following files:

<System>\drivers\DetPort.sys
<System>\drivers\IsPubDrv.sys
<System>\drivers\RvdPort.sys
<System>\winguis.dll

The SYS files are empty and non-malicious.

When first run, Troj/Oscor-B also creates the service GUI30svr

Troj/Oscor-B injects itself in to all running processes and hooks the following APIs:

Kernel32.dll FindFirstFileW
FindNextFileW
Module32NewW
Psapi.dll EnumProcessModules
GetModuleFileNameW
Advapi32.dll EnumServicesStatusA
EnumServicesStatusW
RegEnumKeyA
RegEnumKeyExA
RegEnumKeyExW
RegEnumKeyW
RegEnumValueA
RegEnumValueExA
RegEnumValueExW
RegEnumValueW
RegQueryValueExA
RegQueryValueExW
RegSetValueExA
RegSetValueExW

Troj/Oscor-B creates a hidden instance of Internet Explorer to communicate with the remote server via http POST messages.

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_DLLs

The following registry entry is set:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
AppInit_DLLs
<System>\WINGUIS.DLL

RSS|Atom
Get reports about the latest virus and spyware threats delivered to your computer