CVE-2023-20105 in Expressway
Summary
by MITRE • 06/28/2023
Multiple vulnerabilities in Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an authenticated attacker with Administrator-level read-only credentials to elevate their privileges to Administrator with read-write credentials on an affected system. Note: "Cisco Expressway Series" refers to Cisco Expressway Control (Expressway-C) devices and Cisco Expressway Edge (Expressway-E) devices. For more information about these vulnerabilities, see the Details section of this advisory.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/23/2025
This vulnerability represents a critical privilege escalation flaw in Cisco's unified communications infrastructure, specifically affecting the Expressway Series and TelePresence Video Communication Server platforms. The vulnerability allows authenticated attackers with existing administrator-level read-only credentials to escalate their privileges to full administrator status with read-write capabilities. This represents a significant security weakness in Cisco's access control mechanisms, as it undermines the principle of least privilege and could enable attackers to gain complete control over critical communication systems. The affected devices include Cisco Expressway Control (Expressway-C) and Cisco Expressway Edge (Expressway-E) appliances, which serve as core components in enterprise communication networks and video conferencing solutions.
The technical nature of this vulnerability stems from insufficient input validation and access control checks within the administrative interface of these devices. Attackers can exploit this flaw by leveraging their existing read-only administrative credentials to manipulate the system's privilege structures and gain elevated access rights. This type of vulnerability typically arises from improper implementation of authorization checks or inadequate session management controls that fail to properly validate user permissions at critical points in the application flow. The vulnerability's classification aligns with CWE-284, which addresses improper access control issues in software systems, and represents a clear violation of the principle that users should only be granted the minimum privileges necessary for their legitimate operations.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it could enable attackers to compromise entire communication infrastructures within organizations. Once elevated to full administrator status, attackers could modify system configurations, access sensitive communication data, manipulate user accounts, and potentially establish persistent backdoors within the network. This vulnerability is particularly dangerous in enterprise environments where these devices often serve as central points for video conferencing, collaboration, and communication services. The attack vector requires only authenticated access, making it more accessible than many other privilege escalation vulnerabilities that require additional attack surface exploitation or physical access to the systems.
Organizations should implement immediate mitigations including applying the latest security patches provided by Cisco, reviewing and strengthening authentication mechanisms, and implementing network segmentation to limit access to these critical systems. The vulnerability also highlights the importance of principle of least privilege implementation, where administrative accounts should be granted only the minimum permissions necessary for their specific functions. Security monitoring should be enhanced to detect unusual administrative activities and privilege changes. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and could be leveraged as part of broader attack chains targeting enterprise communication infrastructure, emphasizing the need for comprehensive security controls across all network components including unified communications systems.