Cybercriminals collect a treasure trove of data from Web surfers whose computers are infected with Trojans. That's all-too-common news these days, but a recent case shows that the problem is getting worse. Finjan Inc., which makes secure Web gateway products, discovered a server in Malaysia being used by hackers to store more than 1.4 gigabytes of stolen data. What surprised the Finjan researchers was that the data was stolen from businesses as well as individuals -- and it was amassed in just three weeks.

Yuval Ben-Itzhak, Finjan's chief technology officer, told us that there were other surprises from the discovery of the Malaysian-based "crimeserver" that was being used as a command-and-control center for the Trojans installed on infected PCs around the world.

"Quite often we see end-user online banking information being logged, but on this server we found a lot of business-related data, such as e-mail communications, patient medical histories, and even screenshots of Outlook," he said. This compromised information could lead to a host of problems for an organization, from violations of federal regulations about patient privacy to the loss of critical business information.

Crimeware as a Service

Ben-Itzhak said the crimeserver was left totally open so that data could be accessed by anyone. The Finjan report about the attack surmised that crimeware is evolving with a new and alarming customer-service focus.

"Crimeware has reached a new level of sophistication. After the birth of sophisticated crimeware toolkits, closely followed by Crimeware-as-a-Service (CaaS), we now see the availability of user data as a 'customer' service by granting open access to the crimeware server with the harvested data."

Finjan researchers noted that the Malaysian server had changed hosting locations a number of times between late last year and the time the crimeserver was discovered, "likely to prevent it from being closed down by the ISP/hosting provider in case of complaints."

Application Exploits

The stolen data came to the crimeware server after Web surfers were infected via well-known vulnerabilities, Ben-Itzhak said. "We found several Internet Explorer, Yahoo Messenger, and AOL Messenger vulnerabilities that were used to exploit the browsers of those who were visiting the sites," he said. "Once the browser exploit is running, the Trojan is installed."

He told us that neglecting to update third-party applications creates an opportunity for infection. "People and businesses are making a lot of effort to install updates from Microsoft every second Tuesday of the month, but they forget to install updates of the other applications running in Windows like instant messaging, Flash and PDF, and that's exactly where these criminals are going now."

Keeping operating systems and other applications (including Skype, WinZip, and other non-Microsoft software) updated and patched will help minimize the risk of infection by Trojans, Ben-Itzhak advised. He added that reactive security measures such as signature-based antivirus and URL filtering were important steps, but said they should be augmented with proactive measures that detect malicious code based on suspicious behavior (for example, trying to install software or send out data).

Those measures are critical, he said, because while the Malaysian crimeware server was quickly shut down, "the criminal is still there."