According to a three-week study led by Ph.D. student Marco Cova, winner of Symantec Research Labs Graduate Fellowship, Koobface generated 17,170 unique IP addresses, which host social engineering ploys to infect victims with the data-stealing/DNS-changing malware.
"While the central [server] has been actively targeted by takedown requests, the Koobface gang has so far been quick to replace suspended domain names and blacklisted IPs with new ones," Cova said on the Symantec Security Response blog post.
Koobface is best known for attempting to compromise the PCs of users of social networking sites, such as MySpace, Facebook and Twitter. According to Kaspersky Lab, the number of Koobface variants jumped from 109 at the start of the year to nearly 1,000 at the end of June.
Symantec researchers also detected 11,337 malicious blogs, which redirect users to landing pages containing the worm. Victims visit the blogs -- automatically created on Google's Blogspot platform -- through search engine optimization (SEO) tactics.
A Google spokesperson could not immediately be reached for comment.
"More than a year has passed since Koobface was first detected," Cova said. "Yet this worm and the people behind it are still very active in keeping their infrastructure up-to-date, finding new means of propagating the infection and taking advantage of their victims."