Blaster (Malware)

Blaster or Lovesan was a worm directed to computers running the Windows operating system that has spread over the Internet in 2003. Its programming directed a distributed denial of service attack (DDoS) to the Microsoft Windows update site. Infected computers showed system instability which often caused the closure of the system to end the Windows RPC process. The worm used a flaw in this service corrected a month before to be able to replicate. The author of one of the variants of this worm was identified and arrested by the police of the United States, confessing his guilt.

Creation and effects
According to court papers, the original Blaster was created after security researchers from the Chinese group Xfocus reverse engineered the original Microsoft patch that allowed for execution of the attack.

The worm spreads by exploiting a buffer overflow discovered by the Polish security research group Last Stage of Delirium in the DCOM RPC service on the affected operating systems, for which a patch had been released one month earlier in MS03-026 and later in MS03-039. This allowed the worm to spread without users opening attachments simply by spamming itself to large numbers of random IP addresses. Four versions have been detected in the wild. These are the most well known exploits of the original flaw in RPC, but there were in fact another 12 different vulnerabilities which never saw very much media attention.

The worm was programmed to start a SYN flood against port 80 of windowsupdate.com if the system date is after August 15 and before December 31st and after the 15th day of other months, thereby creating adistributed denial of service attack (DDoS) against the site. The damage to Microsoft was minimal as the site targeted was windowsupdate.com, rather than windowsupdate.microsoft.com to which the former was redirected. Microsoft temporarily shut down the targeted site to minimize potential effects from the worm.

The worm's executable, MSBlast.exe. contains two messages. The first reads:

I just want to say LOVE YOU SAN!!

This message gave the worm the alternative name of Lovesan. The second reads:

billy gates why do you make this possible ? Stop making money and fix your software!!

This is a message to Bill Gates, the co-founder of Microsoft and the target of the worm.

The worm also creates the following registry entry so that it is launched every time Windows starts:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\ windows auto update=msblast.exe