CVE-2021-26474 in BDR Suite
Summary
by MITRE • 06/09/2021
Vembu BDR Suite before 4.2.0 allows Unauthenticated SSRF via a GET request that specifies a hostname and port number.
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Analysis
by VulDB Data Team • 06/11/2021
The vulnerability identified as CVE-2021-26474 affects Vembu BDR Suite versions prior to 4.2.0, representing a critical server-side request forgery flaw that enables unauthenticated attackers to perform malicious requests on behalf of the vulnerable system. This vulnerability resides within the application's handling of GET requests that accept hostname and port specifications, creating an avenue for attackers to manipulate the application's behavior by redirecting requests to internal or external targets. The flaw essentially allows an attacker to instruct the vulnerable system to make HTTP requests to arbitrary destinations, potentially exposing internal network resources or facilitating further exploitation.
The technical implementation of this vulnerability stems from insufficient validation and sanitization of user-supplied input parameters within the application's request processing logic. When a GET request is made with specific hostname and port parameters, the system fails to properly validate or restrict these inputs, allowing arbitrary hostnames to be specified. This lack of input validation creates a direct pathway for attackers to bypass normal access controls and potentially access internal services that should otherwise be restricted from external access. The vulnerability operates at the application layer and can be exploited without requiring authentication, making it particularly dangerous as it can be leveraged by anyone with access to the vulnerable system's network.
From an operational impact perspective, this vulnerability presents significant risks to organizations relying on Vembu BDR Suite for backup and recovery operations. Attackers could potentially enumerate internal network services, access sensitive data stored on internal servers, or even perform lateral movement within the network by targeting internal systems that are not directly exposed to external networks. The vulnerability could enable attackers to discover and exploit additional weaknesses in the internal infrastructure, potentially leading to complete system compromise. Additionally, the lack of authentication requirements means that exploitation can occur remotely, making the attack surface much larger and more difficult to monitor or control.
Organizations should immediately implement mitigations including upgrading to Vembu BDR Suite version 4.2.0 or later, which contains the necessary patches to address this vulnerability. Network-level controls such as firewall rules and web application firewalls should be configured to restrict access to the vulnerable endpoints and monitor for suspicious requests. Input validation should be strengthened to ensure that only properly formatted and authorized hostnames and ports are accepted by the application. Regular security assessments and network monitoring should be conducted to detect any exploitation attempts, with particular attention to unusual outbound connections or requests to unexpected destinations. This vulnerability aligns with CWE-918, which addresses server-side request forgery, and maps to ATT&CK technique T1190 for exploitation of remote services and T1071.004 for application layer protocol usage. The vulnerability demonstrates the critical importance of proper input validation and the potential for seemingly simple flaws to create significant security risks in backup and recovery systems.