CVE-2021-1562 in BroadWorks Application Server
Summary
by MITRE • 07/09/2021
A vulnerability in the XSI-Actions interface of Cisco BroadWorks Application Server could allow an authenticated, remote attacker to access sensitive information on an affected system. This vulnerability is due to improper input validation and authorization of specific commands that a user can execute within the XSI-Actions interface. An attacker could exploit this vulnerability by authenticating to an affected device and issuing a specific set of commands. A successful exploit could allow the attacker to join a Call Center instance and have calls that they do not have permissions to access distributed to them from the Call Center queue. At the time of publication, Cisco had not released updates that address this vulnerability for Cisco BroadWorks Application Server. However, firmware patches are available.
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Analysis
by VulDB Data Team • 07/11/2021
The vulnerability identified as CVE-2021-1562 represents a critical authorization flaw within the XSI-Actions interface of Cisco BroadWorks Application Server, a unified communications platform widely deployed in enterprise environments. This weakness stems from inadequate input validation mechanisms that fail to properly verify user permissions before executing sensitive commands. The vulnerability specifically affects the authorization controls that govern access to Call Center functionality, creating a pathway for authenticated attackers to escalate their privileges and gain unauthorized access to protected call resources. The flaw exists at the application layer where user requests are processed, making it particularly dangerous as it requires minimal attack prerequisites beyond valid authentication credentials. Security researchers have classified this issue as a privilege escalation vulnerability that undermines the fundamental security model of the platform.
The technical exploitation of CVE-2021-1562 occurs when an authenticated user leverages improper input validation within the XSI-Actions interface to execute unauthorized commands that should typically be restricted. This flaw allows attackers to manipulate command sequences that control Call Center queue operations, enabling them to join specific Call Center instances and receive calls that fall outside their designated permissions. The vulnerability operates through a command injection pattern where malicious input is processed without adequate sanitization, leading to unauthorized access to call distribution mechanisms. The affected system fails to maintain proper access controls during command execution, allowing attackers to bypass the normal authorization checks that should prevent access to restricted call queues. This represents a classic case of insufficient authorization validation that violates the principle of least privilege, where users can perform actions beyond their intended scope.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential service disruption and unauthorized resource access within enterprise communication systems. An attacker exploiting this vulnerability could gain access to sensitive customer interactions, call recordings, and business-critical communication data that should remain restricted to authorized personnel. The ability to intercept calls from Call Center queues creates opportunities for data breaches, eavesdropping, and potential financial fraud. Organizations relying on Cisco BroadWorks for mission-critical communications face significant risks including compliance violations under data protection regulations such as gdpr and pci dss, as well as potential regulatory penalties for inadequate security controls. The vulnerability's remote exploitation capability means that attackers do not require physical access to the system, making it particularly concerning for organizations with distributed or cloud-based deployments.
Organizations affected by CVE-2021-1562 should immediately implement mitigation strategies while awaiting official patches from Cisco. The primary remediation approach involves applying the available firmware updates that address the input validation and authorization flaws within the XSI-Actions interface. Security administrators should also consider implementing network segmentation to limit access to the affected application server, restricting authentication to trusted networks only. Additional protective measures include monitoring for unusual command execution patterns within the XSI-Actions interface, implementing stricter access controls for Call Center operations, and conducting thorough privilege reviews to ensure users maintain only necessary permissions. The vulnerability aligns with CWE-285, which addresses improper authorization issues, and maps to ATT&CK technique T1078 for valid accounts and privilege escalation. Organizations should also consider implementing comprehensive logging and alerting mechanisms to detect potential exploitation attempts and maintain audit trails for forensic analysis.