How would a program (such as AV) pick up key loggers running on a Windows based system ? Are there internal system processes that are normally invoked to pickup keystrokes ?
I ask because I know there are commercial spyware that are able to hide from anti malware - otherwise how could they prove useful if they are being neutralised by anti malware tool.
Take a look at this thread. Slightly different topic of discussion, but the answer also answers your question. As was stated in that thread, no anti-virus program can detect every key logger, especially given that there are numerous different ways and languages that could be used to create a software based key logger, assuming that's what you're asking about. Some AV software will detect a key logger simply by identifying it as a known key logger by hashing. Some will also detect key loggers by identifying that a process is behaving like a key logger.
