Millions of household routers are susceptible to a flaw that creates a handy means for hackers to hijack surfing sessions or hack into home networks.
Craig Heffner, a researcher at security consultancy Seismic, is due to detail the flaw and release a proof-of-concept tool at the Black Hat conference in Vegas later this month. The DNS rebinding-related security flaw affects kit from Linksys Belkin and Dell, among others.
DNS rebinding have been around for years. Heffner claims he has discovered a new variant of the theme, which initially involves luring a surfer into visiting a website containing malicious code. This code uses a "Jedi-mind trick" to circumvent the same-origin policy, thereby allowing JavaScript-based malware to penetrate private home networks supported by vulnerable hardware.
The sleight of hand discovered by Heffner involves establishing an attack site which runs malicious script that means a visitor's own IP address is presented as one of the site's alternative IP addresses, thereby granting a trusted status to a malign site. Modern browsers are designed to block earlier types of such attacks but not with this particular scenario, for reasons Heffner is due to explain at Black Hat.
The complex attack approach uncovered by Heffner involves either exploiting vulnerable routers or taking advantage of weak (default) hardware passwords, Forbes explains:
http://blogs.forbes.com/firewall/2010/07/13/millions-of-home-routers-vulnerable-to-web-hackA description of Heffner's talk, entitled How to Hack Millions of Routers:
http://www.blackhat.com/html/bh-us-10/bh-us-10-briefings.html#Heffner , on the Black Hat conference website, explains.
"Many consumer routers can be exploited via DNS rebinding to gain interactive access to the router's internal-facing administrative interface. Unlike other DNS rebinding techniques, this attack does not require prior knowledge of the target router or the router's configuration settings such as make, model, internal IP address, host name, etc, and does not rely on any anti-DNS pinning techniques, thus circumventing existing DNS rebinding protections."A full list of vulnerable networking kit can be found on Notebooks.com here:
http://www.notebooks.com/2010/07/15/how-to-secure-your-router-against-a-hack-compromising-many-popular-routers Notebooks.com also lists some sensible workarounds, such as downloading the latest firmware from manufacturers and using strong (hard to guess) passwords.
(ElReg)