CVE-2021-1530 in BroadWorks Messaging Server
Summary
by MITRE • 05/06/2021
A vulnerability in the web-based management interface of Cisco BroadWorks Messaging Server Software could allow an authenticated, remote attacker to access sensitive information or cause a partial denial of service (DoS) condition on an affected system. This vulnerability is due to improper handling of XML External Entity (XXE) entries when parsing certain XML files. An attacker could exploit this vulnerability by uploading a crafted XML file that contains references to external entities. A successful exploit could allow the attacker to retrieve files from the local system, resulting in the disclosure of sensitive information, or cause the application to consume available resources, resulting in a partial DoS condition on an affected system. There are workarounds that address this vulnerability.
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Analysis
by VulDB Data Team • 05/09/2021
The vulnerability identified as CVE-2021-1530 resides within the web-based management interface of Cisco BroadWorks Messaging Server Software, representing a critical security weakness that affects organizations relying on this communication platform. This flaw specifically manifests in the improper handling of XML External Entity (XXE) entries during XML file parsing operations, creating a pathway for authenticated remote attackers to exploit the system. The vulnerability is particularly concerning because it operates within the management interface, which typically requires legitimate credentials to access, making it a sophisticated attack vector that bypasses traditional perimeter security measures.
The technical flaw stems from the software's insufficient validation and sanitization of XML input data, allowing malicious XML files to contain external entity references that can be processed by the application's XML parser. When an attacker uploads a crafted XML file containing XXE payloads, the system's XML parser attempts to resolve these external entity references, creating opportunities for unauthorized data access and system resource consumption. This weakness directly aligns with CWE-611, which categorizes improper restriction of XML external entity reference as a critical vulnerability pattern, and demonstrates how XML parsing errors can be weaponized to extract sensitive information from the server's local file system or to exhaust system resources through resource-intensive processing operations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to partial denial of service conditions that significantly disrupt business operations for organizations using Cisco BroadWorks Messaging Server. Attackers exploiting this vulnerability can potentially retrieve confidential files from the local system, including configuration data, user credentials, or other sensitive information that could be leveraged for further attacks. Additionally, the resource consumption aspect of the vulnerability can cause the application to become unresponsive or partially unavailable, affecting messaging services and potentially compromising the availability of critical communication infrastructure. This dual nature of impact makes the vulnerability particularly dangerous as it can simultaneously compromise confidentiality and availability aspects of the system's security posture.
Organizations affected by this vulnerability should implement immediate mitigations including applying the latest security patches provided by Cisco, which address the XXE processing flaws in the web interface. Network segmentation and access controls should be enhanced to limit access to the management interface to only authorized personnel, while monitoring systems should be deployed to detect unusual XML file uploads or processing activities. The implementation of XML parser configurations that disable external entity resolution and DTD processing can serve as additional protective measures. Organizations should also consider implementing web application firewalls that can detect and block XXE attack patterns, and conduct regular security assessments to identify other potential XXE vulnerabilities in their infrastructure. These measures align with ATT&CK technique T1590, which covers reconnaissance activities involving the identification of vulnerabilities in web applications, and T1190, which addresses exploitation of remote services through XML external entity injection attacks.