For the fourth time in as many months, Cisco has removed hardcoded credentials that were left inside one of its products, which an attacker could have exploited to gain access to devices and inherently to customer networks.

This time around, the hardcoded password was found in Cisco’s Wide Area Application Services (WAAS), which is a software package that runs on Cisco hardware that can optimize WAN traffic management.

Harcoded SNMP community string

This backdoor mechanism (CVE-2018-0329) was in the form of a hardcoded, read-only SNMP community string in the configuration file of the SNMP daemon.

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The string came to light by accident, while security researcher Aaron Blair from RIoT Solutions was researching another WaaS vulnerability (CVE-2018-0352).

This second vulnerability was a privilege escalation in the WaaS disk check tool that allowed Blair to elevate his account’s access level from “admin” to “root.” Normally, Cisco users are permitted only admin access. The root user level grants access to the underlying OS files and is typically reserved only for Cisco engineers.

By using his newly granted root-level access, Blair says he was able to spot the hidden SNMP community string inside the /etc/snmp/snmpd.conf file.

“This string can not be discovered or disabled without access to the root filesystem, which regular administrative users do not have under normal circumstances,” Blair says.

Source: Cisco Removes Backdoor Account, Fourth in the Last Four Months