Vulnerabilities / Threats

How 'Postcript' Exploits Networked Printers

At Black Hat 2017, a university researcher will demo how attackers can drill into networked printers by way of the ubiquitous PostScript programming language.

Network printer exploits are like old dogs learning new tricks, according to a security researcher with Ruhr University.

In his upcoming Black Hat presentation, Exploiting Network Printers, Jens Muller, Ruhr University chair for network and data security will delve into an analysis of printer attacks, in which he discovered 20 printer models were all vulnerable to at least one of the same attacks that he tested. Muller will also disclose unusual ways the Internet is enabling network printer attacks via advanced cross-site printing techniques.

The vulnerability, Muller says, stems from the 35-year-old PostScript programming language, which has connected printers to end-users for decades, even as technology evolved from the parallel printer cable, to the USB stick, to networked printers, and today to the cloud.

"Before, printers used parallel cables and having PostScript wasn't a problem." Muller says. "But now, the printer manufacturers are still using PostScript and they can easily be exploited remotely."

PostScript: An Industry Standard 

The PostScript programming language is an industry standard for network printers and its use is ubiquitous. But despite attackers ability to exploit this language, printer manufacturers have largely looked the other way, he says. Instead, manufacturers put the onus on network administrators to place the printers inside the network, where the devices are presumed to be protected from outside threats.

Even today, he notes, manufacturers do not seem to realize that attackers can drill into networked printers by way of the Internet.

On the networking side, network administrators tend to view their connected printers as nothing more than a printing device, as opposed to a potential vector of attack, he says, noting that the end result is that network admins may not think it's important to secure network printers.

Some of the attacks Muller has tested include a denial of service attack that damaged eight of the 20 printers he was testing. One new issue to emerge is the ability to set a printer back to its factory defaults by taking control of the printer remotely. Other printer attacks range from stealing print jobs containing sensitive information to pilfering system files.

Work Arounds

One potential solution to the problem, Muller says, is to corral all the connected printers and put them on a separate network with a print server. The downside: it would require a network administrator to oversee two networks, which, he says, could be difficult for midsized companies and result in the additional costs of installing and monitoring a second firewall.

"What CISOs should really do is ask themselves do they really need a device connected," Muller says. "It may make sense not to connect the printer to the cloud."

Related Content:

Dawn Kawamoto is an Associate Editor for Dark Reading, where she covers cybersecurity news and trends. She is an award-winning journalist who has written and edited technology, management, leadership, career, finance, and innovation stories for such publications as CNET's ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Crowdsourced vs. Traditional Pen Testing
Alex Haynes, Chief Information Security Officer, CDL,  3/19/2019
BEC Scammer Pleads Guilty
Dark Reading Staff 3/20/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: Well, at least it isn't Mobby Dick!
Current Issue
5 Emerging Cyber Threats to Watch for in 2019
Online attackers are constantly developing new, innovative ways to break into the enterprise. This Dark Reading Tech Digest gives an in-depth look at five emerging attack trends and exploits your security team should look out for, along with helpful recommendations on how you can prevent your organization from falling victim.
Flash Poll
The State of Cyber Security Incident Response
The State of Cyber Security Incident Response
Organizations are responding to new threats with new processes for detecting and mitigating them. Here's a look at how the discipline of incident response is evolving.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-4035
PUBLISHED: 2019-03-22
IBM Content Navigator 3.0CD could allow attackers to direct web traffic to a malicious site. If attackers make a fake IBM Content Navigator site, they can send a link to ICN users to send request to their Edit client directly. Then Edit client will download documents from the fake ICN website. IBM X...
CVE-2019-4052
PUBLISHED: 2019-03-22
IBM API Connect 2018.1 and 2018.4.1.2 apis can be leveraged by unauthenticated users to discover login ids of registered users. IBM X-Force ID: 156544.
CVE-2019-9648
PUBLISHED: 2019-03-22
An issue was discovered in the SFTP Server component in Core FTP 2.0 Build 674. A directory traversal vulnerability exists using the SIZE command along with a \..\..\ substring, allowing an attacker to enumerate file existence based on the returned information.
CVE-2019-9923
PUBLISHED: 2019-03-22
pax_decode_header in sparse.c in GNU Tar before 1.32 had a NULL pointer dereference when parsing certain archives that have malformed extended headers.
CVE-2019-9924
PUBLISHED: 2019-03-22
rbash in Bash before 4.4-beta2 did not prevent the shell user from modifying BASH_CMDS, thus allowing the user to execute any command with the permissions of the shell.