CVE-2021-1276 in Data Center Network Manager
Summary
by MITRE • 01/21/2021
Multiple vulnerabilities in Cisco Data Center Network Manager (DCNM) could allow an attacker to spoof a trusted host or construct a man-in-the-middle attack to extract sensitive information or alter certain API requests. These vulnerabilities are due to insufficient certificate validation when establishing HTTPS requests with the affected device. For more information about these vulnerabilities, see the Details section of this advisory.
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Analysis
by VulDB Data Team • 02/18/2021
Cisco Data Center Network Manager DCNM version 11.5.1 and earlier contains multiple vulnerabilities that enable attackers to perform man-in-the-middle attacks and spoof trusted hosts through inadequate certificate validation during HTTPS communications. These security flaws specifically affect the certificate validation mechanisms implemented in the HTTPS request establishment process, creating opportunities for attackers to intercept and manipulate API communications between clients and the DCNM server. The vulnerabilities stem from insufficient validation of SSL/TLS certificates, allowing adversaries to present fraudulent certificates that the system accepts as legitimate, thereby undermining the security of encrypted communications. This weakness directly relates to CWE-295, which addresses improper certificate validation in secure communications, and aligns with ATT&CK technique T1573.002 for securing communications protocols. The impact of these vulnerabilities extends beyond simple information disclosure, as they enable attackers to modify API requests in transit, potentially compromising the integrity of network management operations and allowing unauthorized modifications to critical data center configurations. Attackers exploiting these flaws could gain access to sensitive operational data, including network configuration details, user credentials, and system information that would normally be protected by HTTPS encryption. The vulnerabilities are particularly concerning in data center environments where DCNM serves as a central management platform, as successful exploitation could lead to complete compromise of network management capabilities and potential lateral movement within the data center infrastructure. Organizations using affected DCNM versions face significant risk of unauthorized access to critical network management functions, with potential for cascading security impacts across the entire data center network ecosystem.
The insufficient certificate validation mechanisms present in DCNM create a pathway for attackers to establish fraudulent HTTPS connections that appear legitimate to the system. This occurs because the software does not properly verify certificate chains, validate certificate expiration dates, or ensure that certificates match the expected hostnames during the SSL/TLS handshake process. The vulnerability allows for certificate pinning bypasses and enables attackers to perform successful man-in-the-middle attacks against API endpoints that should only be accessible through secure encrypted channels. This weakness is particularly dangerous because it affects the fundamental security layer that protects API communications, potentially allowing attackers to intercept and modify sensitive data exchanges between network management tools and the DCNM server. The attack surface includes all HTTPS connections made to the DCNM API endpoints, making it possible for adversaries to monitor traffic, inject malicious payloads, or extract confidential information without detection. This vulnerability type is classified under CWE-310, which specifically addresses cryptographic weaknesses in certificate validation processes, and represents a critical failure in the secure communication architecture of the affected system.
Organizations utilizing Cisco DCNM in their data center environments must urgently address these vulnerabilities through immediate patching and configuration updates to prevent potential exploitation. The recommended mitigation strategy involves upgrading to Cisco DCNM version 11.5.2 or later, which contains fixes for the certificate validation issues. Network administrators should also implement additional security controls including monitoring for unusual API access patterns, implementing network segmentation to limit access to DCNM management interfaces, and conducting thorough security assessments of all network management systems. The vulnerabilities present in DCNM 11.5.1 and earlier versions represent a significant risk to enterprise network security, as they allow attackers to bypass the primary security controls protecting network management communications. Security teams should also consider implementing additional monitoring and alerting mechanisms specifically designed to detect man-in-the-middle attack attempts against HTTPS endpoints. These measures are particularly important given that the attack vector involves the fundamental security protocol of HTTPS, making detection challenging and potentially allowing for long-term undetected access to critical network management functions. The combination of information disclosure and potential request manipulation capabilities makes this vulnerability particularly dangerous in environments where DCNM serves as the primary interface for managing critical network infrastructure components.