Netgear has promised to release a patch next month to fix a recently discovered vulnerability that lets attackers take control of unguarded kit.
Security flaws in the firmware that ships with the latest versions of Netgear's WNDR3700 wireless router mean that miscreants can bypass authentication before accessing the administrative interface controlling the networking hardware, according to security blogger Zach Cutlip.
The Tactical Network Solutions security researcher warns that open access to the admin panel of the router opens the door up to all manner of malfeasance.
With complete, persistent administrative access to the web interface, a huge attack surface is opened up. A malicious DNS server could be configured, exposing users to web browser exploits. Ports could be forwarded to devices on the LAN, exposing vulnerable services to attack.
Or, a trojan horse firmware could be flashed onto the device that would give the attacker persistent root-level access to the router. Additionally, any command injection or buffer overflow vulnerabilities in the router's web interface become fair game once authentication is disabled.
Cutlip added that the vendor's attempts to suggest that this is a LAN-only vulnerability offers only false reassurance in many cases.
"Remote administration is an option that is available in the router's configuration interface, and many users have turned it on," he told El Reg
To support his point, Cutlip pointed towards Shodan search queries revealing WNDR3700v4 devices with administration exposed to the internet in hundreds of cases. Shodan is a search engine that, in skilled hands, can easily be used to index vulnerable routers, printers, servers and internet-accessible industrial control systems.
"Some (though not all) of Netgear's devices that have this vulnerability, are also vulnerable to Reaver," Cutlip added. "This means in a matter of a few hours, an attacker outside the physical premises can compromise the device's WPS, extract the WPA encryption key, and join the LAN in order to attack the device."
Cutlip added that he discovered authentication bypass bug and the command injection bug in a matter of minutes back in June this year. "It is surprising to me that Netgear's internal security testing didn't find these bugs before the products shipped," he concluded.
In a blog post, he added: "Because there are almost certainly fools who would go hack somebody's router and say I told them to do it, I added a warning to not do this. DON'T DO IT."
Jacob Holocomb, of Independent Security Evaluators, found a similar bug in a different Netgear device, the WNDR4700, back in April.
Netgear responded to our request for comment on Cutlip's discovery by admitting a problem but suggesting that, in practice, it's only exploitable by a hacker of the same network, which can be secured to defend against attack. Nonetheless, the networking equipment firm promised to develop a patch to safeguard against exploits, which it plans to release sometime next month, as explained below.
We are aware of the recent discussions of security vulnerabilities on some Netgear routers. As always we are very vigilant about any new threats and take immediate actions to fix them.
We are already working on a patch which should be released by next month-Nov’13.
The specific security issue in discussion requires the hacker to be on the router's LAN network- Wi-Fi/Wired/or through remote access; this is the first level of security breach that customers need to defend themselves from. All Netgear Wi-Fi routers ship with pre-configured Wi-Fi security enabled, which we highly recommend customers use this default Wi-Fi security configuration to ensure their home network is secure.
The discovery of a "backdoor" into the admin panel of home networking kit from Netgear caps a miserable few weeks for router security firm.
Earlier this month security researcher Craig Heffner discovered a similar backdoor on a range on routers from D-Link. In response, D-Link promised to close its routers' backdoors by Halloween (31 October).
Pending the availability of a fix. users of the vulnerable kit are advised to disable remote access to their routers and make sure their wireless networks are secure, advice that parallels morsels offered by rival Netgear in the latest case.
Heffner followed up his research by discovering another backdoor, this time in wireless networking kit from Chinese firm Tenda. Attackers could gain unauthenticated access to the routers’ administrative interfaces through the built in web server on affected models, providing they had first managed to hop onto the same network as their intended victim. Tenda released a fix on Thursday, as explained in an advisory here.
The wireless router security issue is unrelated to a serious command-injection flaw in Netgear ReadyNAS storage kit that made the news earlier this week. Netgear patched the flaw in July, but recently released internet scans conducted by IT security firm Tripwire discovered that around three in four users had failed to apply the fix, leaving themselves dangerously exposed to attack as a result. ®