A vulnerability in a Time Warner cable modem and Wi-Fi router deployed to 65,000 customers would allow a hacker to remotely access the device's administrative menu over the internet, and potentially change the settings to intercept traffic, according to a blogger who discovered the issue.

Time Warner acknowledged the problem to Threat Level on Tuesday, and says it's in the process of testing replacement firmware code from the router manufacturer, which it plans to push out to customers soon.

"We were aware of the problem last week and have been working on it since," said Time Warner spokesman Alex Dudley.

The vulnerability lies with Time Warner's SMC8014 series cable modem/Wi-Fi router combo, made by SMC. The device is one of several options Time Warner offers to customers who don't want to install their own modem and router to use with the company's broadband service. The device is installed with default configurations, which customers can alter only slightly through its built-in web server. The most customers can do through this page is add a list of URLs they want their router to block.

But blogger David Chen, writing at chenosaurus.com, recently discovered he could easily gain remote access to an administrative page served by the router that would allow him greater control of the device.

Chen, founder of a software startup called Pip.io, said he was trying to help a friend change the settings on his cable modem and discovered that Time Warner had hidden administrative functions from its customers with Javascript code. By simply disabling Javascript in his browser, he was able to see those functions, which included a tool to dump the router's configuration file.

That file, it turned out, included the administrative login and password in cleartext. Chen investigated and found the same login and password could access the admin panels for every router in the SMC8014 series on Time Warner's network – a grave vulnerability, given that the routers also expose their web interfaces to the public-facing internet.

All of this means that a hacker who wanted to target a specific router and change its settings could access a customer's admin panel from anywhere on the net through a web browser, log in with the master password, and then start tinkering. Among the possibilities, the intruder could alter the router's DNS settings – for example, to redirect the customer's browser to malicious websites – or change the Wi-Fi settings to open the user's home network to the neighbors.

The attacker would need the router's IP address to conduct the attack. But Chen found a dozen customer SMC8014 series cable modem/Wi-Fi routers by simply running a port scan on a subnet of 255 Time Warner IP addresses. An evil hacker could easily automate a scanning tool to sweep through Time Warner's address space and hack every SMC8014 it finds.

"From within your own network, an intruder can eavesdrop on sensitive data being sent over the internet and even worse, they can manipulate the DNS address to point trusted sites to malicious servers to perform man-in-the-middle attacks," Chen wrote on his blog. "Someone skilled enough can possibly even modify and install a new firmware onto the router, which can then automatically scan and infect other routers automatically."

Chen said he contacted Time Warner’s security department four weeks ago and was told that the company was aware of the security vulnerability but “cannot do anything about it.”

He says he's relieved to hear the company is now addressing the problem.

It's unclear if other Time Warner customers would be affected by the same issues.

Time Warner's Dudley says the SMC8014 modem/routers are just a small portion of the 14 million devices its customers are using.

"We are working to determine if it affects other models," he says.

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