Reasons Why You May Not Be Able to Remove a Spyware/Malware Infection

Malware has become more and more sophisticated in recent years, evolving from annoyance attacks or proof-of-concept attacks to rootkits and keyloggers designed to steal your personal and critical data. Each day we face new and even more insidious threats with that may have the follow characteristics:

    • The infection on your computer may have a morphic quality. There are two types of morphic code a computer virus may exhibit: Polymorphic and Metamorphic.Polymorphic: The first technique that posed a serious threat to virus scanners. Just like regular encrypted viruses, a polymorphic virus infects files with an encrypted copy of itself, which is decoded by a decryption module. In the case of polymorphic viruses, however, this decryption module is also modified on each infection. A well-written polymorphic virus therefore has no parts which remain identical between infections, making it very difficult to detect directly using signatures.

      Metamorphic: To avoid being detected by emulation, some viruses rewrite themselves completely each time they are to infect new executables. Viruses that use this technique are said to be metamorphic. A metamorphic virus is usually very large and complex.


    • Manual removal tends to leave behind hidden files. Some viruses try to trick anti-virus software by intercepting its requests to the operating system. A virus can hide itself by intercepting the anti-virus software’s request to read the file and passing the request to the virus, instead of the Operating System. The virus can then return an uninfected version of the file to the anti-virus software, so that it seems that the file is "clean".


  • You did not update your spyware removal tool. As computers and operating systems grow larger and more complex, old hiding techniques need to be updated or replaced. Defending a computer against viruses may demand that a file system migrate towards detailed and explicit permission for every kind of file access. It is therefore very important to update your spyware removal tool as often as possible to keep up with these constantly changing trends.