Despite Stone's reassurances, Mikko Hypponen, chief researcher at F-Secure, said further attacks occurred Monday. "Twitter administrators don't seem to be able to shut down the various XSS/CSRF worms that have been plaguing the service over the weekend," he said in a blog post. "The actual problems to end users haven't been devastating -- so far. Most of the Twitter worms simply modify people's profiles to infect more users. However, attacks like these could be much worse if the attackers would incorporate nastier attacks, such as browser exploits."
Hypponen observes that the latest worm attack uses the bit.ly URL shortening service to redirect victims to an infected profile. URL shortening services like bit.ly have been criticized recently for various reasons, one of which is the security implications of disguised URLs.
Last month, Secure Science researchers Lance James and Eric Wastl said Twitter was vulnerable to a serious XSS vulnerability that could allow an attacker to hijack users' accounts or, in conjunction with other exploit code, compromise their computers.
The Twitter worm that struck over the weekend appears to make use of a different XSS vulnerability. Its code has been posted on GitHub, a collaborative programming code repository.
A post on the Secure Science blog warns that the viral effect of social networks magnifies the impact of viral computer code. "[W]hen vulnerabilities are found such as cross-site scripting, this viral effect may be easily abused and produce a detrimental outcome such as infecting account holders and possibly crashing the social network," the company said.
According to online news site BNOnews.com, a 17-year-old from Brooklyn, N.Y., identified as Mikeyy Mooney, claimed responsibility for creating the Twitter worm to drive traffic to his Web site, StalkDaily.com.
A request for comment sent to StalkDaily.com was not answered.
Attend a Webcast on why bad security breaches keep happening to good organizations. It happens Wednesday, April 15. Find out more and register.