Trend Micro: Thousands Of Government Computers Infected By Bots

Security vendor Trend Micro, which has been studying the phenomenon and is pushing a service to detect bots, reports finding a bot infestation in government computers. Its list of bot-bitten organizations includes the Department of Defense, the Navy Network Information Center, the Pittsburgh Supercomputing Center, Argonne National Laboratory, and the Navy Regional Data Automation Center. At the state level, its list includes the Alabama Supercomputer Network, Arkansas Department of Information Systems, Iowa Communications Network, and Connecticut's Department of IT.

Trend Micro planned to disclose its findings this week -- ostensibly in the interests of public awareness. But as InformationWeek followed up with organizations cited by Trend Micro, some of the vendor's conclusions were called into question, owing in part to the complexity of tracking these zombie computers. One national laboratory, for example, was initially identified as having compromised machines, but the lab disputed those findings and subsequent analysis by Trend Micro revealed that the spam in question doesn't appear to have come from computers that were hosted at the lab. Trend Micro has since postponed its announcement and is double-checking the 60 terabytes of data it used to trace spam to bot-infected computers.

At the time this article was filed, Trend Micro said that data pointing to the presence of bots at the Pittsburgh Supercomputing Center and the Navy Network Information Center remained uncertain.

Trend Micro attempts to identify compromised machines by analyzing spam samples received from customers of its filtering service. It's tricky work, because bot creators employ techniques for covering their tracks. "You have no idea how complex this is," says Dave Rand, Trend Micro's CTO. After initially claiming that "tens of thousands" of government computers had bots within them, Rand this week downgraded the tally to 7,000.

That doesn't mean bots aren't a problem—they most certainly are for government agencies and businesses alike. Trend Micro estimates there are 70 million subverted computers worldwide and that 8 million to 9 million are used to send spam in a given month. In general, about 60% of zombies are used to send spam and 40% for more destructive means, including phishing, pharming, click fraud, distributing adware or malware, denial of service attacks, surreptitious data theft, and temporarily storing illegal, malicious or stolen files.

While most everyone agrees that the attacks are getting larger, more frequent, and more sophisticated, not everyone sees evidence that bots are a growing problem among government computers. Network security specialist Prolexic says there's been an increase in the size of distributed denial of service attacks from 3.5 gigabits per second last year to over 10 Gbps in 2006, yet a data sample from the company's clients doesn't show evidence of those attacks originating from government Internet addresses. That finding is based on about 40 DDoS attacks monitored by Prolexic in the first seven months of 2006.

After being contacted by InformationWeek, Prolexic operations VP Matt Wilson did a quick search of the company's computer logs for evidence of bot attacks originating from government computers. "I didn't see anything that would have indicated mass bot infections within any government agencies or networks," he says. "That is not to say that they do not exist, simply that they aren't being used to attack our customer base."

It's small comfort, however, because if government systems are being hijacked, it could be for more devious purposes. "Something like that would be much more valuable for targeted mining of things like passwords, e-mail addresses, mapping out government networks," Wilson says.

Data maintained by e-mail security vendor IronPort confirms the presence of spam-sending bots on government networks. IronPort reports a 40% increase in spam volume since February across government and business accounts. Craig Sprosts, a senior product manager at IronPort, notes that the percentage of spam coming from government accounts is minor—1% to 2% of the overall problem—compared to what is originating from ISPs and other compromised networks. Security vendor MX Logic also confirms the presence of compromised computers at government addresses. "We are seeing some botnet spam from government networks but the volume appears to be fairly low," says Sam Masiello, director of threat management for MX Logic. "I'm not surprised that the numbers are low, but there is obviously some vulnerability." "Fairly low" in this case means that less than 1% of the spam messages received over the past week by the company's Threat Center on behalf of over 10,000 organizations around the world came from U.S. government IP addresses.

In fact, this is consistent with what Trend Micro is reporting: The US government and contractor sector represents approximately 0.035% of the total number of hosts sending spam worldwide.

Not Immune

Bots land on computers in many ways, including operating system or application vulnerabilities, dictionary attacks that guess passwords, a pre-existing backdoor created by a prior computer virus, and malicious files downloaded via e-mail, IM, or peer-to-peer applications. Bots are frequently installed as a result of human error—opening a malicious file or visiting an unsafe Web site, for example. Once installed, bots may be able to update themselves or install other malicious software. They're typically controlled though commands received from an Internet Relay Chat server, and any compromised PC can be turned into an IRC server that can then be used to coordinate a bot network.

Increasingly, bots are using encrypted or covert channels of communication rather than IRC, which can easily be blocked, and they come with keylogging and screen capture capabilities, says Masiello.

A spokesman for the Department of Defense declined to address specific security concerns, including bots, but he acknowledged that the DoD's computer systems are attacked daily. "The DoD aggressively responds to deter all intrusions," says Major Patrick Ryder via e-mail. "We're not immune, but we have a layered defense in place." Among the steps it takes: intrusion detection software, firewalls, and increased awareness training of personnel.

Mike Skwarek, cyber security program manager and deputy CIO at Argonne National Labs, had not seen the Trend Micro findings nor talked to the security vendor early this week as this story was being researched. But based on the description of Trend Micro's findings—that spam received from the vendor's customers points to Argonne as one source of the problem—Skwarek doesn't believe the assertions and points to spoofing as a possible explanation. "You can forge where e-mails are coming from. It's quite easy," he says.

Once or twice a week, Argonne gets complaints about being a source of spam. Usually, however, its own analysis of the evidence will show that the lab wasn't actually at fault—that a suspect PC was turned off at the time, for instance. If an Argonne PC gets infected by a bot, all e-mail is blocked from the infected PC. "We have an early warning, and that's effective," Skwarek says. Argonne has had two viruses in the past year and a half that may have been related to a bot infection, but those viruses were quickly detected and removed. "We do a good job on the desktop fighting this," Skwarek says.

While it may be tempting to discount the warnings of security vendors as self serving—bot fever means more business for Trend Micro—there's unanimity about the growing risk of cybercrime. In its list of the top 10 computer security developments to watch for in 2007, released last week, the SANS Institute warns that targeted attacks will become more prevalent, particularly against government agencies. "Targeted cyber attacks by nation states against U.S. government systems over the past three years have been enormously successful, demonstrating the failure of federal cyber security activities," SANS director of research Alan Paller says in an e-mail. "Other antagonistic nations and terrorist groups, aware of the vulnerabilities, will radically expand the number of attacks."

Network security vendor Arbor Networks last month reported that DDoS attacks and botnets are the most significant security threat facing ISPs. Arbor contends that bot command and control networks are harder to infiltrate and that today's bots are more powerful than their ancestors, as well as more difficult to find and remove.

Scott Chasin, CTO of MX Logic, concurs: "Botnets are the most dangerous enemy that the Internet has faced up until now.

-- Larry Greenemeier and Marianne Kolbasuk McGee contributed to this article