Cisco IOS FTP Backdoor Ripe for Hackers

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Another flaw in Cisco’s IOS, this time a problem with FTP, the mechanism used to update the firmware on Cisco devices (routers & switches mostly).

You really don’t want someone playing around with your configuration files on your router do you?

IOS FTP, which comes disabled by default in IOS, is used to upload IOS software images and other software to routers and switches remotely. However, Cisco says attackers could exploit a vulnerability in the FTP server to gain access to the file system of an IOS-based router or switch and affect configuration settings.

“Unauthorized users could retrieve the device’s startup-config file from the filesystem,” Cisco says.”This file may contain information that could allow the attacker to gain escalated privileges.”

You can shutdown the FTP service on the IOS for the moment to be safe, and wait for the update.

The command is detailed below:

You could also setup an access control list to limit access to FTP.

In the meantime, Cisco says users should shut down IOS FTP if they are running the server on an affected system. (The command to do this is ‘ftp-server enable’.) The company says users can upload software to IOS devices through other methods, such as the ‘Secure Copy’ feature in the software. Users can also set up access control lists to restrict FTP access to a router or switch, Cisco adds.

The affected IOS versions are: 11.3, 12.0, 12.1, 12.2, 12.3 and 12.4. Cisco’s IOS XR is not vulnerable, and non-IOS Cisco devices are also safe.

So be careful if you are using Cisco kit, this is quite a bad hole.

Source: Network World