CVE-2020-3267 in Unified Contact Center Express
Summary
by MITRE
A vulnerability in the API subsystem of Cisco Unified Contact Center Express (Unified CCX) could allow an authenticated, remote attacker to change the availability state of any agent. The vulnerability is due to insufficient authorization enforcement on an affected system. An attacker could exploit this vulnerability by authenticating to an affected system with valid agent credentials and performing a specific API call with crafted input. A successful exploit could allow the attacker to change the availability state of an agent, potentially causing a denial of service condition.
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Analysis
by VulDB Data Team • 10/21/2020
The vulnerability identified as CVE-2020-3267 resides within the API subsystem of Cisco Unified Contact Center Express, a critical component of Cisco's contact center solutions that manages agent interactions and call routing. This weakness represents a significant authorization bypass issue that undermines the security posture of enterprise communication systems. The vulnerability specifically affects the authentication and access control mechanisms that govern agent availability states, creating a pathway for malicious actors to manipulate core operational functions without proper authorization.
The technical flaw manifests through insufficient authorization enforcement mechanisms within the API layer of Unified CCX. When an authenticated attacker with valid agent credentials makes a specific API call with crafted input parameters, the system fails to properly validate the request's legitimacy. This authorization gap allows the attacker to manipulate agent availability states through programmatic interfaces that should otherwise be restricted to authorized administrative functions. The vulnerability stems from inadequate input validation and access control checks that should have prevented unauthorized state modifications.
Operationally, this vulnerability creates substantial risk for organizations relying on Cisco Unified CCX for customer service operations. An attacker who successfully exploits this weakness can manipulate agent availability states to disrupt service delivery, potentially causing cascading failures throughout the contact center infrastructure. The impact extends beyond simple denial of service to include potential data integrity issues, as unauthorized state changes may affect call routing decisions, reporting accuracy, and overall system reliability. This vulnerability particularly threatens organizations with high agent turnover or those operating under strict service level agreements where agent availability directly impacts customer experience metrics.
Organizations should implement immediate mitigations including strengthening authentication mechanisms, implementing network segmentation to limit API access, and deploying monitoring solutions to detect unauthorized API calls. The vulnerability aligns with CWE-285, which addresses improper authorization issues in software systems, and maps to ATT&CK technique T1078 for valid accounts and T1499 for endpoint disruption. Network administrators should consider implementing API rate limiting and access control lists to restrict API endpoints from unauthorized networks. Regular security assessments of the Unified CCX environment should include thorough testing of authorization controls and input validation mechanisms to prevent similar vulnerabilities from being exploited in production environments.