Securing Network Printers

By Abdul Saboor Malik •  Updated: 04/17/19 •  2 min read

IoT is among many buzz words of today and is one of the technologies guiding our future lifestyle. According to data and analytics company, Global Data, the IoT business is projected to reach $318bn by 2023.   Given this, there is a high interest in IoT.

However, the security of IoT is a growing concern as more and more devices are connected online and are likely to be hacked and exploited due to their poor security features.

Network printers are now widely connected all over the internet and are quite useful. Unfortunately, as an IoT device facing the public internet, printers are very vulnerable due to their protocol design.

Recently, in the Black Hat 2018. A security researcher made a comprehensive presentation on how the printers are so vulnerable. There is a lot of technical details discussed in his talk. All tech-savvy people can go through this link:

In short, network printers work on a protocol such as PostScript and PJL that can be used easily to manipulate print jobs and access sensitive files. The talk also suggested some ways that can be employed to secure the network printers. Here is the list of steps to take:

1.    Make sure the printers are unconnected to the public internet and are not accessible via public IP.

2.    Prevent physical access to the printing rooms. Ensure that device rooms are locked and provided with enough physical protection measures such as locks, cameras etc.

3.    The printers at the network level should have security enhanced. The network administrators should harden the printer server security through separating print VLANs and hardening with the print server.

4.    Vendors should focus on long-term redesigning of insecure PJL and postscripts and data encoding over the same channels.

5.    Browsers should be configured to block access to port 9100 that can be used to send malware and obtain print jobs.

6.    Administrators should ensure the password protection of the printer’s device to protect against any rough attacks such as pass-back attacks.

Abdul Saboor Malik

Internet Governance Activist | Information Security Expert | CyberSecurity Blogger | Digital Grassroot Ambassador