Microsoft Leads Effort To Disrupt Dorkbot Botnet

Microsoft researchers, working in tandem with other researchers and law enforcement officials in several countries, helped disrupt a malware family dubbed Dorkbot that is believed to have infected more than 1 million computers worldwide.

Researchers from Microsoft’s Malware Protection Center and Digital Crimes Unit teamed up with counterparts at ESET and CERT Polska in providing detailed information and telemetry on Dorkbot to law enforcement in the US, Canada, and Europe. US-CERT, the FBI, Interpol, and the Royal Canadian Mounted Police, all worked on the case.

Microsoft yesterday in a post announcing the Coordinated Malware Eradication (CME) campaign  offered no details on how exactly Dorkbot was disrupted. But ESET said the effort had involved sinkholing the command and control servers that threat actors were using to remotely control compromised systems.

Dorkbot is malware that first surfaced in April 2011 and has been used since then to steal passwords and personal information from people logging into sites like Facebook, Gmail, Netflix, PayPal, Twitter, and YouTube.

The malware works by disabling security software on a system and then blocking access to the security websites that update the software. Once on a system, Dorkbot connects via Internet Relay Chat to a remote command and control server and downloads other malware on to it. Compromised systems become part of large Dorkbot botnets used in denial-of-service attacks and for spam distribution purposes.

The malware spreads through removable drives, drive-by downloads, spam emails, instant messaging clients, and social networks.  Microsoft said that over the past six months, it detected an average of 100,000 Dorkbot infected systems per month, largely in India, Indonesia, and the Russian federation. A Microsoft “heat map” showing Dorkbot machine detections over the past three months shows the U.S. as having a relatively large number of infected systems as well.

“Dorkbot is an old botnet that has been reinventing itself through the years,” malware researcher Jean-Ian Boutin wrote on the ESET blog. “Dorkbot uses old tricks to compromise new systems.” 

Dorkbot’s creator or creators have made the malware available as a ready-to-use kit called NgrBot, which is available to criminals through underground forums, Microsoft said. The kit comes with a complete set of instructions on how to create a botnet and helpfully lists all the different functions that are available and how to use them. Included in the documentation are tips for command settings and IRC settings.

Microsoft’s Coordinated Malware Eradication campaign, launched in January 2014, is an effort to get security vendors, researchers and other stakeholders to pool their resources and information in coordinated, large scale anti-malware campaigns. The company has said that it is only through coordinated efforts that the industry has a chance to deter destructive malware campaigns.

According to Microsoft, security vendors can help by sharing malware data and detection methods with law enforcement. Computer emergency response teams and Internet Services Providers can help by blocking or taking down known malware sites and command and control servers, while financial services companies can help by choking off the money supply to known criminals, Microsoft says.