Updated If you get your internet service from O2, there's a good chance Paul Mutton can remotely log in to your router and make configuration changes that surreptitiously allow him to access computers on your network.
That's because the UK-based ISP offers its customers free customized routers that are vulnerable to CSRF, or cross-site request forgery, attacks. Simply put, the hole allows him to log into the device using a simple web browser and a specially manipulated URL. Once connected, he can perform many if not all of the same administrative tasks an owner physically accessing the device can.
"This flaw allows remote attackers to take almost full control of the router, including stealing the wireless encryption key (even if the most advanced WPA2 setting was enabled) and forwarding external ports to internal IP addresses," Mutton, a security researcher located near the UK's Bath, wrote here.
The port-forwarding bit makes it easy easy for an attacker to intrude into a user's home network by burrowing into a computer, set-top box, or other device that would otherwise be protected by router's firewall. Interlopers can probably do other things, including changing the domain name system server to one that silently redirects users to rogue websites that masquerade as a legitimate bank, e-commerce site or search engine.
The flaw resides in two custom-built devices O2 gets from router manufacturer Thomson. Both the TG585n, and the TG585, known respectively as the O2 Wireless Box III and the O2 Wireless Box II, suffer from the bug. Subscribers of other ISPs that use the device are also likely to be exposed to the same threat.
An O2 spokesman said: "We have been notified of a potential security issue with the O2 Wireless box routers. We take this issue very seriously and are investigating it with the router manufacturer, Thomson. We thank Mr Mutton for bringing it to our attention."
Mutton said that's a far cry from the statements O2 support people gave him over the past week when he tried to bring the vulnerability to their attention. According to the blow-by-blow he provided, they told him the devices were "secured to a standard that is acceptable for home use" and that the provider was "under no obligation to supply you with a different router."
Routers and other low-cost devices that come with web interfaces have long been known to be vulnerable to a wide variety of attacks. Routers seem to be the low-hanging fruit, with bugs having been found in gear made by Linksys and Netgear and devices provided by BT on multiple occasions. ®
On Thursday, O2 issued the following statement:
"Having been notified of a potential security issue with our O2 wireless box we have been working to find a solution. We have taken this issue very seriously and have been continuing to investigating it with the router’s manufacturer, Thomson.
"As a result we have identified a solution and we will be applying this remotely to all of our customers O2 wireless boxes. This means that customers will not have to take any action themselves."