There are various types of malware infections which can cause redirects. The most common we see is related to TDL3
), the third and fourth generation of the TDSS rootkit
. TDSS hides itself on a system by infecting system files/drivers like atapi.sys, a common target because it loads early during the boot process and is difficult to detect. Newer varinats of TDL3 can target a number of other legitimate drivers in the Windows drivers folder while TDL4 generally infects the Master Boot Record (MBR)
. The latest variants even have a a self-propagation mechanism
For more specific analysis and explanation of the infection and it's history, please refer to:
These are .pdf documents with more comprehensive information.
There are various tools which have been created to deal with this malware (i.e. TDSSKiller, Norman TDSS Cleaner, FixTDSS (Backdoor.Tidserv Removal Tool) by Symantec, BitDefender TDSS/TDL4 Removal Tool). However, the malware writers keep changing TDSS in order to avoid disinfection so sometimes a tool works while other times it may not. Another problem is that many times an infection will download additional malicious files which complicate the removal process so the symptoms and extent of damage will vary. This could include backdoor Trojans
, and IRCBots
all of which are very dangerous
because they compromise system integrity
by making changes that allow it to be used by the attacker for malicious purposes. They can disable your anti-virus and security tools to prevent detection and removal
. Remote attackers use backdoors as a means of accessing and taking control of a computer that bypasses security mechanisms. This type of exploit allows them to steal sensitive information like passwords, personal and financial data which is then sent back to the hacker.
Many experts in the security community believe that once infected with this type of malware, the best course of action is to wipe the drive clean, reformat
and reinstall the OS. Please read:
Backdoors and What They Mean to You
Whenever a system has been compromised by a backdoor payload, it is impossible to know if or how much the backdoor has been used to affect your system...There are only a few ways to return a compromised system to a confident security configuration. These include:
• Reimaging the system
• Restoring the entire system using a full system backup from before the backdoor infection
• Reformatting and reinstalling the system
This is what Jesper M. Johansson at Microsoft TechNet has to say: Help: I Got Hacked. Now What Do I Do?
The only way to clean a compromised system is to flatten and rebuild. That’s right. If you have a system that has been completely compromised, the only thing you can do is to flatten the system (reformat the system disk) and rebuild it from scratch (reinstall Windows and your applications).
Edited by quietman7, 28 July 2011 - 06:31 AM.