The security researchers at eEye Digital Security are not impressed with the Sasser worm

The company, which found the flaws that were exploited by both the MSBlast worm and the Witty worm, on Saturday started analyzing the latest piece of attack code that takes advantage of a Microsoft Windows vulnerability discovered by its researchers. So far, eEye's analysts are surprised that the worm has spread so far. The Sasser worm started spreading late Friday, and so far has not racked up the crowd of compromised computers that its predecessors have been able to claim. Such a limited spread could indicate that computer users are becoming more diligent about heeding warnings and patching their systems, but security researchers believe that the worm's poor programming has given network administrators a break. "If this virus was better written, you would have seen more impact," said Alfred Huger, senior director of security firm Symantec's response center. The Sasser worm spreads from infected computer to vulnerable computer with no user interaction required. The worm exploits a recent vulnerability in a component of Microsoft Windows known as the Local Security Authority Subsystem Service, or LSASS. After scanning for vulnerable Windows XP and Windows 2000 systems, the worm creates a remote connection to the system, installs a file transfer protocol (FTP) server and then downloads itself to the new host.