Cycle.A is a worm that spreads via the Internet by exploiting the LSASS vulnerability in remote computers. This vulnerability is critical only for Windows XP/2000 operating systems that are not properly updated.
Cycle.A restarts the computer automatically when it attempts to exploit the already mentioned vulnerability.
Cycle.A only spreads automatically to Windows XP/2000 computers. However, computers with other Windows operating systems can also be a source of transmission when a malicious user runs the file containing the worm in any of these computers.
Cycle.A ends the processes belonging to the worms Blaster, Sasser.A, Sasser.B, Sasser.C and Sasser.D.
In addition, it launches DoS (Denial of Service) attacks against the web sites www.irna.com (Islamic Republic News Agency) and www.bbc.com (British Broadcasting Corporation) when the system date is not between May 1 and May 18, inclusive.
If you have a Windows 2003/XP/2000/NT computer, it is highly recommendable to download the security patches for the LSASS vulnerability from the Microsoft website.