updated 02:13 am EST, Fri November 30, 2012
Flaw in Samsung's SNMP implementation to blame for exploit
Printers manufactured by Samsung have been found to have a glaring security weakness -- most all models built before October 31, 2012 have a backdoor administrator account that could enable attackers to modify configurations, read network information, access stored credentials, and potentially execute malicious code. The SNMP account in the printers reportedly has full read and write permissions, and remains accessible to network assault even when turned off using the printer's maintenance utility.
The US Computer Emergency Readiness Team (US-CERT) said in a report about the flaw that "Samsung has also indicated that they will be releasing a patch tool later this year to address vulnerable devices." The group recommends that users restrict access to the printers, allowing SNMP access only from trusted host IP addresses, MAC address filtering, or only allowing access from network segments known to be safe, which would limit the ability of hackers to use the hardcoded credentials.
US-CERT did not publicize a list of affected printers, but noted that Dell-branded printers manufactured by Samsung were affected by the flaw as well. Disabling SNMPv1 and 2 on a network-level will prevent this exploit from being executed. SNMPv3 mode is considered secure.