The Klez worm was first detected in October 2001 and, more often than not, arrived attached to an email.
Klez exhibited traits of different types of malware, appearing as a worm, virus or Trojan horse.
Klez wasn’t as damaging as some of the other notorious worms I’ve written about before but it is still active today, albeit to a far lesser degree than in 2002.
In fact, it would probably be fair to say that no other worm has stayed in circulation for quite as long as Klez has.
As I mentioned at the beginning, Klez was most often distributed as an email attachment.
If you became infected by this worm it would scour your email address book, looking for both incoming and outgoing contacts to whom it would then send itself to.
Klez would often entice users to open it up by posing as a worm-removal tool which reminds me of the antivirus scams we see today.
The damage cause by Klez wasn’t so severe – it would corrupt some files – but it did disable antivirus programs.
The worm is quite rare now but hasn’t gone away completely so ensure that you have your computer protected at all times with a good antivirus program.
Read more : Malware That Changed The World