Canon MFPs Vulnerable to FTP Bounce Attack

Researchers at Indiana University have raised an alert for a difficult-to-fix vulnerability affecting certain Canon Multifunction printers.

The flaw, which affects about 20 different Canon MFP models, could allow remote attackers to redirect traffic to other sites via the PORT command.

This issue is known as FTP bounce and is related to an old issue in FTP servers that lets remote attacker to connect to arbitrary ports on machines other than the FTP client.

According to the Indiana University advisory, the following Canon products are affected:

• imageRUNNER 2230/2830/3530
• imageRUNNER 3025/3030/3035/3045
• imageRUNNER 2270/2870/3570/4570
• imageRUNNER 5070/5570/6570
• imageRUNNER 5050/5055/5065/5075
• imageRUNNER 8070/85+/9070/105+
• imageRUNNER 7086/7095/7105
• Color imageRUNNER C3220/2620
• Color imageRUNNER C2880/3380
• Color imageRUNNER C2550
• Color imageRUNNER C4080/4580/5180/5185
• Color imageRUNNER LBP5960
• Color imageRUNNER LBP5360
• imageRUNNER C3170
• imageRUNNER C5800/6800
• imageRUNNER C5870U/6870U
• imageRUNNER C5058/5068
• imageRUNNER LBP3460
• imagePRESS C7000VP
• imagePRESS C1

[ Also see: Multifunction Printers: The Forgotten Security Risk ]

Canon has acknowledged the issue in an alert (PDF) that warns that an attacker may be able to scan networks that are not otherwise accessible. "An attacker may also be able to conceal the true origin of a port scanning attempt," Canon said, noting, however, that information in the network host cannot be obtained via the affected printers.

Nate Johnson, the lead security engineer at Indiana University who reported the issue to Canon, said the available firmware updates that fix the vulnerability "are not user-installable."

"[Patching this] requires a service-technician call from a local Canon Authorized Service Dealer," Johnson said.

As a temporary mitigation, Johnson recommends:

Disable FTP printing:

• Navigate to Additional Functions -> System Settings -> Network Settings -> TCP/IP Settings -> FTP print.
• Set FTP print to OFF.

Protect FTP printing with username/password credentials:

• Navigate to Additional Functions -> System Settings -> Network Settings -> TCP/IP Settings -> FTP print.
• Set "user name" and "password" for the FTP print functionality.

"Additionally, best practices suggest that access controls and network firewall policies be put into place to only allow connections from trusted machines and networks," Johnson said.