Cisco on Wednesday announced the availability of patches for a critical authentication bypass vulnerability in Enterprise NFV Infrastructure Software (NFVIS) for which proof-of-concept exploit code already exists.
Enterprise NFVIS is a piece of infrastructure software that helps organizations deploy virtualized network functions, including virtual routers and firewalls, on supported Cisco devices, while also providing centralized management and support for automated provisioning.
Tracked as CVE-2021-34746 (CVSS score of 9.8), the newly patched vulnerability was identified by Orange Group security researcher Cyrille Chatras. Proof-of-concept (PoC) exploit code for this flaw “is available.”
The issue resides in the TACACS+ authentication, authorization and accounting (AAA) feature of Enterprise NFVIS and exists because user supplied input is not completely validated when passed to an authentication script.
Because of this bug, an unauthenticated, remote attacker could inject parameters into an authentication request and exploit the vulnerability to bypass authentication and log in to an affected device as administrator.
The security hole affects Enterprise NFVIS release 4.5.1, but only if the TACACS external authentication method is configured, Cisco says.
While no workarounds exist to mitigate the vulnerability, Cisco has released software updates to address the bug. Enterprise NFVIS releases 4.6.1 and later contain the patches.
Cisco says that, although PoC code that exploits the vulnerability exists, it is not aware of malicious attacks targeting vulnerable products.
Cisco has also released patches for four medium-severity vulnerabilities impacting Prime Infrastructure and Evolved Programmable Network (EPN) Manager, Prime Collaboration Provisioning, Identity Services Engine (ISE) Software, and Nexus Insights.
Details on all of the addressed vulnerabilities are available on Cisco’s security portal.