Home / malware Virus:W32/Tenga.A
First posted on 19 April 2010.
Source: SecurityHomeAliases :
Virus:W32/Tenga.A is also known as W32/Gael.worm.a (McAfee), Virus:Win32/Gael.A (Microsoft), PE_TENGA.A (Trend Micro), W32.Licum (Symantec).
Explanation :
A program that secretly and maliciously integrates itself into program or data files. It spreads by integrating itself into more files each time the host program is run.
Additional DetailsVirus:W32/Tenga.A is a virus that infects all executable files.
On executing the infected file, the virus attempts to contact a remote server and download and execute a file. In addition, the virus installs a remote command shell on the infected machine.
Infection
Tenga.A infects files by appending itself to each Windows executable file it finds. The virus also has the ability to scan the network and infect files found in open network shares.
It avoids infecting ntoskrnl.exe and marks each infected executable files with the character `V´ in the old DOS stub header. The marking of the infected files prevents re-infection attempts
To check if an instance of itself is already running, the virus creates a mutex named gaelicum.
Execution
Upon execution, it connects to and tries to download and execute http://utenti.lycos.it/[***]/dl.exe
It also connects to http://[***].users.freebsd.at and opens a remote command shell on the affected machine on port 54321.
The virus uses CRC matching to search for the required APIs it needs to do its malicious tasks.
Tenga.A also elevates its privileges and disables Windows File Protection.DetectionF-Secure Anti-Virus detects this malware with the following updates:
[FSAV_Database_Version]
Version = 2005-07-14_01.Last update 19 April 2010
