A new security feature added to some D-Link wireless routers actually makes users more susceptible to network intrusion, according to a hacker blog, which provides enough evidence to be taken seriously.
Manufacturer D-Link was still busy congratulating itself for adding a CAPTCHA designed to prevent malware bots from logging on to the devices when folks at the SourceSec Security Research blog showed how the upgrade could be manipulated to steal a WPA (or Wi-Fi protected access) password without even bothering to solve the test.
That's because the new firmware logs in using a GET request containing a salted MD5 hash of the password, along with with input that's unique to the CAPTHCHA image. It turns out all that's required to access the router's setup page is the hash, so the feature provides an easy way for anyone within range to access the panel that controls all kinds of sensitive settings and contains the WPA password.
What's more, the new firmware allows even those with user-level access the ability to log in to the control panel, so an attacker need not have administrative credentials to perform the attack.
When we learned earlier this week that D-Link added the CAPTCHA to some of its home and office routers, we dismissed it as little more than a gimmick designed to lull inattentive consumers into a false sense of security. After all, it does nothing that couldn't be achieved by taking 30 seconds to change the default password to a phrase that's strong and unique.
Now we learn that it can actually make it easier for people within range to sneak into private sections of a network and uses the notoriously insecure MD5 hash to boot. Now that's something worth writing about. ®