Download the authoritative guide: Cloud Computing 2019: Using the Cloud for Competitive AdvantageThe 802.1x port-based security standard is often considered the best method of security for network access control (NAC) implementations. But that's not to say that all 802.1x implementations are always secure and bug-free.
Cisco this week reported that a pair of its 802.1x supplicants (an 802.1x component used in the client endpoints) had flaws that, if exploited, could have allowed an attacker to gain user privileges, modify files or otherwise damage the availability or confidentially of the system.
The Cisco Secure Services Client (CSSC) and a lightweight version of CSSC included in the Cisco Trust Agent (CTA) within the Cisco Network Admission Control (NAC) Framework had privilege escalation and password disclosure vulnerabilities that Cisco has now corrected.
Cisco has fixed four different privilege escalation bugs. According to Cisco's advisory, one of the bugs could potentially have allowed an unprivileged user who is logged into the computer to increase their privileges to the local system user via the help facility within the supplicant Graphical User Interface (GUI).
Cisco also fixed an unintentional password disclosure bug. The advisory notes that with certain authentication methods, a user password is logged in cleartext (i.e. non-obfuscated or encrypted) in the respective application's log files.
Cisco is not the only vendor that uses 802.1x as a method for deploying NAC. StillSecure and others, such as Cisco, in the NAC space, also provide alternatives to 802.1x, including DHCP and inline approaches.