Sasser

Worm Sasser is a well-known Internet spyware that infects vulnerable PCs, which have security breaches. It doesn't distribute itself by e-mail or some networks, but infects PCs directly and doesn't depend on the user's actions. It installs itself to the computer and searches for other vulnerable hosts. The worm can hang the infected PC or reboot it frequently. It also severely compromises the security of infected computers, so the attackers are able to connect and control them remotely.