German Police Snag Phatbot Author

A 21-year-old German man was arrested and has admitted to creating the ubiquitous and dangerous Trojan horse programs Agobot and Phatbot, but he is not connected to the German author of the Sasser Internet worm, a police spokesman said.

German police arrested the man on Friday in the southern German town of Waldshut and charged him under the country's computer sabotage law for attacks linked to Agobot and Phatbot on computers in Germany, the U.K., and the U.S.

Five other men were also charged in connection with the so-called Trojan programs, but there is no link between them and the 18-year-old author of the Sasser Internet worm, said Horst Haug, a spokesman for the State Bureau of Investigation in Baden-Wuerttemberg.

Mission Accomplished?

Authorities arrested the Phatbot author, a "self-taught" hacker, following tips in recent weeks from the U.S. Federal Bureau of Investigation, Haug said. Police searched the suspect's home and seized computer hardware, software, and documents, he said.

Agobot is a Trojan horse program that surreptitiously runs on computers using Microsoft's Windows operating systems, providing malicious hackers with secret access to the compromised system. Since first appearing in October 2002, hundreds of versions of Agobot have been detected, including variants called, variously, Gaobot, Phatbot, and Polybot.

The computer code for Agobot circulates widely on the Internet and may have been modified by countless individuals with access to it, said Mikko Hyppönen, manager of antivirus research at F-Secure in Helsinki.

Despite that, German authorities believe they have the original author of the Trojan, Haug said.

"He confessed to being the original author. He said he created both Agobot and Phatbot," he said.

Other Arrests

Two other Waldshut men were also arrested on Friday in connection with the Agobot Trojan. Arrests in the case were also made in Bavaria, Lower Saxony, and Hamburg, Haug said. The men are believed to have worked together to make Trojan horse programs and "other viruses," Haug said.

Also on Friday, police in Lower Saxony, in northern Germany, arrested an 18-year-old and charged him with creating the Sasser worm, which appeared on May 1. That man is also being investigated on suspicion of creating the Netsky worm, but he does not appear to be connected to the Agobot group, Haug said.

Information provided to the authorities leading to the Sasser arrest came from Microsoft rather than the FBI, and German authorities do not believe the two groups of malicious code writers knew each other or worked together, Haug said.

The Sasser arrest followed a tip to Microsoft Deutschland GmbH from individuals who asked about the possibility of receiving a reward in exchange for information about the creator of the Sasser worm, said Brad Smith, senior vice president and general counsel at Microsoft, in a statement.

"It doesn't seem like there is any direct connection," he said.

Analyzing Evidence

Prior to the arrests, however, officials were not sure whether the groups communicated with each other, and so timed their arrests in the two cases to prevent crucial evidence from being destroyed, Haug said.

German police are currently analyzing the information seized in the arrests Friday, but have not identified any of the suspects they have arrested, or described the evidence against them, he said.

F-Secure has provided information to authorities on Agobot and Phatbot before, including the Internet Relay Chat log files containing user names and the Internet Protocol addresses of individuals who were selling customized versions of the Trojan horse program online, Hyppönen said.

The capture of the original Agobot author will increase the pressure on others who create malicious programs. However, the availability of the Agobot and Phatbot source code makes it almost certain that new versions of the Trojan will continue to appear, he said.