Who's Hijacking Internet Routes?Attacks Increase, But There's No Easy Fix in Sight
Information security experts warn that Internet routes are being hijacked to serve malware and spam, and there's little you can do about it, simply because many aspects of the Internet were never designed to be secure.
The Internet hijacking problem relates to Border Gateway Protocol, which is responsible for routing all Internet traffic. In the words of Dan Hubbard, CTO of OpenDNS Security Labs: "BGP distributes routing information and makes sure all routers on the Internet know how to get to a certain IP address."
BGP provides critical Internet infrastructure functionality, because the Internet isn't a single network, but rather a collection of many different networks. Accordingly, BGP routing tables give the different networks a way to hand off data and route it to its intended destination.
That assumes, of course, that no one tampers with BGP routing, in which case they could reroute traffic or disguise malicious activity. "The trouble is it ... all relies on trust between networks, so if someone hijacks an ISP router, you wouldn't know," Alan Woodward, a visiting professor at the department of computing at England's University of Surrey, and cybersecurity adviser to Europol, tells Information Security Media Group. "It's just another example of how people are forgetting that the Internet was never built to be a secure infrastructure, and we need to be mindful of that when relying upon it."
Spam, Malware, Bitcoins
Hijacking router tables could allow an attacker to spoof IP addresses and potentially intercept data being sent to a targeted IP address. Thankfully, Woodward says, that is "not a trivial task," and Internet service providers have some related defenses in place.
But some attacks get through. One four-month campaign, spotted by Dell Secureworks in 2014, involved redirecting traffic from major Internet service providers to fool bitcoin-mining pools into sharing their processing power - which is used to generate bitcoins - with the attacker. Dell estimates that the attacker netted about $84,000 in bitcoins, although it's not clear that such attacks are widespread.
What has been on the increase, however, are incidents in which malware and spam purveyors hijack an organization's autonomous system numbers, or ASNs, which indicate how traffic should move within and between multiple networks, says Doug Madory director of Internet analysis at Dyn Research, which was formed after Dyn last year acquired global Internet monitoring firm Renesys.
In a blog post, Madory describes six recent examples of bogus routing announcement campaigns, some of which remain under way, and all of which have been launched from Europe or Russia. By using bogus routing, attackers with IP addresses that have been labeled as malicious - for example by the Zeus abuse tracker, which catalogs botnet command-and-control servers - can hijack legitimate IP address space and trick targeted autonomous systems on the Internet into thinking the attack traffic is legitimate.
"These are not isolated incidents," Madory says of the recent attacks that he has documented. "First, these bogus routes are being circulated at a near-constant rate, and many separate entities are engaged in this practice, although with subtle differences in approach. Second, these techniques aren't solely for the relatively benign purpose of sending spam. Some of this host address space is known to circulate malware."
One takeaway, Madory says, is that any information security analysts who review alert logs should know that the IP addresses attached to alerts may have often been spoofed via BGP hijacking. "For example, an attack that appeared to come from a Comcast IP located in New Jersey may have really been from a hijacker located in Eastern Europe, briefly commandeering Comcast IP space," he says.
The security flaws associated with BGP that allow such attacks to occur haven't gone unnoticed. In January, the EU cybersecurity agency ENISA urged all Internet infrastructure providers to configure Border Gateway Protocol to ensure that only legitimate traffic flows over their over networks.
But ENISA's advice belies that while BGP can be fixed, it can't be done quickly. "There are efforts to cryptographically sign IP address announcements," Madory says. "However, these techniques aren't foolproof and until they achieve a critical mass of adoption, they won't make much difference."
No Quick Fix
"Why Is It Taking So Long to Secure Internet Routing?" is the title of a recent research paper from Boston University computing science professor Sharon Goldberg, who notes that any fix will require not just a critical mass, but coordinating thousands of different groups. "BGP is a global protocol, running across organizational and national borders," the paper notes. "As such, it lacks a single centralized authority that can mandate the deployment of a security solution; instead, every organization can autonomously decide which routing security solutions it will deploy in its own network." That's one reason why BGP hasn't gotten a security makeover, despite weaknesses in the protocol having been well-known by network-savvy engineers for the past two decades.
Lately, however, BGP abuse has been rising. "It appears to be more systematized now," Dyn's Madory warns. Pending a full fix, he says that service providers might combat these attacks by banding together and temporarily blocking Internet traffic from organizations that repeatedly fail to secure their infrastructure, thus allowing BGP attackers subvert it.
In the meantime, keep an eye on security logs for signs of related attacks. "There's no easy defense, but it is kind of possible [to spot attacks] by monitoring and watching for unexpected changes in routing," Woodward says.