Standing up a sinkhole server is one way to catch bots or botnet traffic inside an enterprise. A sinkhole grabs incoming traffic from bot-infected machines trying to communicate with their command-and-control servers. Researchers also use sinkholes to catch and redirect botnet traffic. To date, it has mostly been a homegrown effort used by security researchers, such as the Shadowserver Foundation.
"Sinkholing is one technique that allows security researchers/responders the ability to monitor botnets, as well as proactively deny access to the bots from the botnet herders," says Shaun Vlassis, a member of The Honeynet Project. "Up until the release of HoneySink, all the sinkhole deployments out there have been point solutions with varying degrees of sophistication. All of them are inside jobs, from sinkhole setups that are consisting of DNS plus Apache, to full-blown setups like what Shadowserver employs."
Security firm Unveillance uses sinkhole servers to pose as botnet servers that capture communique from orphaned bots. It controls a large portion of the Qakbot botnet's command-and-control infrastructure via its sinkhole servers.
HoneySink, which was written by a student under the mentorship of Vlassis during the recent Google Summer of Code program, was built to handle large volumes of traffic. Unlike most homegrown sinkholes, it supports multiple protocols.
"The project is a real benefit to organizations -- or anyone, really -- that wants to have sinkholing capabilities but not develop one in-house," says Steven Adair, of Shadowserver, which runs a large sinkhole environment of its own. "Alternatively, a number of organizations traditionally put up a Web server and try and have it handle everything.
"This project lets you take it a step further and emulate a variety of services, so not everything is an HTTP-based response back to connecting clients. Even better is that as the project matures, it will surely continue to have new features and benefit the community even further -- all at no cost."
The Honeynet Project's Vlassis says the sinkhole server could be used by organizations that don't have gateway-filtering devices or SIEM systems as a way to pinpoint infected machines in their networks. "Instead of having to go through the process of getting a domain taken over -- as is on the Internet side of things -- all they would need to do is keep a list of malware domains to redirect their internal staff DNS queries to point to the sinkhole," he says.
Vlassis says so far he has received a lot of interest in HoneySink from the researcher community. The tool supports flat file, MySQL, and MQueue for logging, and can be used as an Internet-facing node configured with its own DNS server "to respond to requests for malicious domains" that researchers, CERTs, and law enforcement, have taken over. It lets them find bot-infected machines and to derail the bot herders.
The beta version of HoneySink is available here for download.
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