The Blaster Worm (also known as Lovsan, Lovesan or MSBlast) was a computer worm that spread on computers running the Microsoft operating systems: Windows XP and Windows 2000, during August 2003.[1]
The worm was first noticed and started spreading on August 11, 2003. The rate that it spread increased until the number of infections peaked on August 13, 2003. Filtering by ISPs and widespread publicity about the worm curbed the spread of Blaster.
On August 29, 2003, Jeffrey Lee Parson, an 18-year-old from Hopkins, Minnesota was arrested for creating the B variant of the Blaster worm; he admitted responsibility and was sentenced to an 18-month prison term in January 2005.[2]
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According to court papers, the original Blaster was created after a Chinese cracking collective called Xfocus reverse engineered the original Microsoft patch that allowed for execution of the attack.[3]
The worm spread by exploiting a buffer overflow discovered by the Polish cracking group Last Stage of Delirium[4] 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.[5]
The worm was programmed to start a SYN flood on August 15, 2003 against port 80 of windowsupdate.com, thereby creating a distributed denial of service attack (DDoS) against the site. The damage to Microsoft was minimal as the site targeted was windowsupdate.com instead of windowsupdate.microsoft.com to which it was redirected. Microsoft temporarily shut down the targeted site to minimize potential effects from the worm.
The worm contains two messages in its source code. The first:
I just want to say LOVE YOU SAN!!
is why the worm is sometimes called the Lovesan worm. The second:
billy gates why do you make this possible ? Stop making money
and fix your software!!
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
Although the worm can only spread on systems running Windows 2000 or Windows XP (32 bit) it can cause instability in the RPC service on systems running Windows NT, Windows XP (64 bit), and Windows Server 2003. In particular, the worm does not spread in Windows Server 2003 because it was compiled with the /GS switch, which detected the buffer overflow and shut the RPCSS process down.[6]When infection occurs, buffer overflow makes RPC service crash, leading Windows to display following message and then automatically reboot, usually after 60 seconds. (default RPC service failure behaviour) [7]
| “ | System Shutdown:
This system is shutting down. Please save all work in progress and log off. Any unsaved changes will be lost. This shutdown was initiated by NT AUTHORITY\SYSTEM Time before shutdown: hh:mm:ss Message: Windows must now restart because the Remote Procedure Call (RPC) Service terminated unexpectedly. |
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This was the first indication many users had an infection; it often occurred a few minutes after every startup on compromised machines. A simple resolution to stop countdown is to run the "shutdown -a" command in the Windows command line, causing some side effects such as an empty (without users) Welcome Screen. The Welchia worm had a similar effect. No more than a year later, the Sasser worm surfaced, which caused a similar message to appear.