Threat behavior
VirTool:Win32/Tibs.E.dll is a user-mode rootkit that may be dropped to the Windows system folder as a file named taskdir.dll. The DLL injects itself into certain processes found running on the system.
On a Windows NT-based system (such as Windows XP or Windows Server 2003), VirTool:Win32/Tibs.E.dll intercepts certain process calls in order to:
- Hide all processes belonging to executables which contain the string "taskdir" in the file name (for example, taskdir.exe).
- Hide registry value names that contain the string "taskdir".
- Hide all folders and files containing the string "taskdir" from Windows Explorer and other GUI-based folder and file viewers.
On non-NT-based systems (such as Windows 98 or Windows ME), for each process into which the DLL is injected, if the name of the executable spawning the process contains the string "taskdir", VirTool:Win32/Tibs.E.dll registers the process as a service. Service processes do not appear in Windows Task Manager under these operating systems.
The VirTool:Win32/Tibs.E.dll code is written in x86 assembly language.
This software threat is detected by the Microsoft antivirus engine.
Prevention