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Panda Protection

Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.

Cycle.A

Threat LevelModerate threatDamageHighDistributionNot widespread
Common name:Cycle.A
Technical name:W32/Cycle.A.worm
Threat level:Low
Type:Worm
Effects:  

It restarts the computer when it exploits the LSASS vulnerability. It launches Denial of Service attacks against the web sites www.irna.com and www.bbc.com.

Affected platforms:

Windows 2003/XP/2000/NT/ME/98/95

Detection updated on:May 10, 2004
StatisticsNo

Brief Description 

    

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.

Visible Symptoms 

    

Cycle.A is easy to recognize, as it restarts Windows XP/2000 computers when it attempts to affect them by exploiting the LSASS vulnerability. When this action is carried out, Cycle.A displays the following message on screen: