The infamous Heartbleed bug doesn't affect home routers in practice, according to new analysis by security researchers at TripWire.
The infosec vendor nevertheless warned that "critical security flaws" are "endemic" to small office/home office (SOHO) routers.
TripWire came to this conclusion after revisiting earlier research on router security in the home and in business in the wake of last month's fear-inspiring OpenSSL security bug, which created a means to lift sensitive data from the memory of a wide variety of computing equipment – including web servers and networking equipment.
“SOHO routers may have code vulnerable to Heartbleed but most of the time it’s not accessible to remote attackers by default," explained Craig Young, security researcher at Tripwire. "Unless the router has a really ridiculous design where packet buffers are in the same heap memory range as OpenSSL buffers, the relative risk from Heartbleed pales in comparison to the many other critical security flaws that affect the vast majority of these products."
Heartbleed is really only a problem for home routers with remote management enabled over HTTPS using a vulnerable installation, and guest network routers in corporations which have management over HTTPS enabled and exposed to the guest network, according to TripWire.
"In either case, the risk added by Heartbleed is negligible in comparison to serious risks associated with the many other critical security flaws that are endemic to SOHO routers. With Heartbleed, the worst case scenario is that someone might get a password or session cookie if there is an active (or very recent) login session but we have found that in many of these routers you can simply bypass the authentication altogether."
A survey by TripWire of home users revealed that most people aren’t logging into their routers regularly enough basis to make it realistic that an attacker would be able to leverage Heartbleed to get password from the router memory even if a targeted device happened to be vulnerable.
Kasper Lindgaard, head of research at vulnerability management firm Secunia, agreed with TripWire's assessment that home routers are among the least troublesome aspect of the Heartbleed security mess.
"Generally speaking, then yes, very few home routers are vulnerable to Heartbleed," Lindgaard told El Reg. "Many of them don’t bundle a vulnerable version of OpenSSL, and if they do, it would require that remote management was enabled, or some other feature that required OpenSSL were available from remote."
"Vendors such as Belkin, D-Link, and TrendNet have not reported any of their models to be affected by Heartbleed.
Lindgaard was nonetheless careful to say that the risk could not safely be ignored. "If a router is vulnerable to Heartbleed from remote, then I would not say that it is neglectable, as the major portion of vulnerabilities in home routers requires either some kind of social engineering or the attacker to be within the same network as the router," he explained.
TripWire has put together six tips for securing home routers to mitigate against many security vulnerabilities and configuration problem endemic in the class of kit.
Four in five of Amazon’s top 25 best-selling SOHO wireless router models have security vulnerabilities, Young previously discovered, hence the need to keep abreast of router firmware updates as well as the need to choose strong passwords and enable encryption, among the points raised in its top tips.
What SHOULD give you the Heartbleed fear?
The main front in the fight against Heartbleed continues to lie in the domain of web servers, even though a wide range of computing equipment is potentially affected. For example, at least 2,500 website administrators have made their previously secure sites vulnerable to Heartbleed more than a month after the bug surfaced, new research by Opera Software developer Yngve Pettersen has revealed.
Meanwhile, Rob Graham of Errata Security separately discovered that about half of vulnerable servers identified after the Heartbleed disclosure were still exposed. He reckons the population of vulnerable servers has dropped from about 600K to 300K in the space of a month since the infamous bug was revealed in early April.
Admins blocking scans and other factors means that both results are indicative of the general state of play rather than a precise tally of the percentage of Heartbleed-vulnerable web servers, which other experts have told us dropped off quickly in the aftermath of the discovery of the important security flaw.
Secunia has written Heartbleed-related advisories for more than 80 vendors and over 500 products. Lindgaard sees efforts to patch up systems in response to the bug as a multi-faceted project not focused on any particular area of technology.
"I don’t think that there is a simple 'main' front," he said. "Many different applications are vulnerable to Heartbleed. The most important first step is to identify and patch the vulnerable software that handles the most critical information and which is reachable from remote."
"After that, a risk assessment containing both attack vector and criticality of the data should be performed," he added. ®