Backdoor access in Samsung printers

A researcher has alerted the U.S. Computer Emergency Readiness Team (US-CERT) that Samsung printer firmware contains a hardcoded backdoor administrator account that could allow remote network access exploitation and device control.

The admin account does not require verification, opening up the devices and users' networks to potentially serious remote attacks.

At the time of making the vulnerability note public US-CERT reported:

Samsung has stated that models released after October 31, 2012 are not affected by this vulnerability.
Samsung has also indicated that they will be releasing a patch tool later this year to address vulnerable devices.

When asked for comment Samsung's Public Relations Manager told:

Samsung is committed to releasing updated firmware for all current models by November 30, with all other models receiving an update by the end of the year.

Security researcher Neil Smith reported the discovery to US-CERT on November 26. Mr. Smith has since published details of the Samsung Printer SNMP Backdoor to his Tumblr.

So if you have a Samsung printer that isn't one month old, until Samsung releases its patch US-CERT tells us that some printer owners might be vulnerable to:

A remote, unauthenticated attacker could access an affected device with administrative privileges. Secondary impacts include: the ability to make changes to the device configuration, access to sensitive information (e.g., device and network information, credentials, and information passed to the printer), and the ability to leverage further attacks through arbitrary code execution.

A successful attacker could almost certainly read print jobs. People assume that what's going to their printer is private - such as payroll data, tax forms, contracts, etc.

At this time, Samsung appears to have pulled all of its printer firmware from its support pages.

Samsung printers contain a hardcoded SNMP full read-write community string. According to US-CERT. it remains active even when SNMP is disabled in the printer management utility.

This runs counter to what Samsung's Public Relations Manager announced via email saying, "The issue affects devices only when SNMP is enabled, and is resolved by disabling SNMP. However, for customers that are concerned, we encourage them to disable SNMPv1,2 or use the secure SNMPv3 mode until the firmware updates are made."

Some Dell printers manufactured by Samsung also have the admin account backdoor access.

In case you're not familiar, SNMP is an Internet-standard protocol that network administrators use to manage connected devices such as routers, servers, printers, hubs and more.

Smith tweeted, "This isn't remote code execution. But it allows for remote firmware update over the wire."

US-CERT recommends users implement general security prophylactics until the issue is resolved: namely, restricted device access and to "only allow connections from trusted hosts and networks."

Samsung's full statement:

Samsung is aware of and has resolved the security issue affecting Samsung network printers and multifunction devices.

The issue affects devices only when SNMP is enabled, and is resolved by disabling SNMP.

We take all matters of security very seriously and we are not aware of any customers who have been affected by this vulnerability.

Samsung is committed to releasing updated firmware for all current models by November 30, with all other models receiving an update by the end of the year.

However, for customers that are concerned, we encourage them to disable SNMPv1,2 or use the secure SNMPv3 mode until the firmware updates are made.

For further information, customers may contact Samsung customer service at 1-866-SAM4BIZ for business customers or 1-800-SAMSUNG for consumers.

Visit priceless-inkjet.com if you need ink or toner for your printer.

Source: Researcher reveals backdoor access in Samsung printers