CVE-2021-4075 in Snipe-IT
Summary
by MITRE • 12/07/2021
snipe-it is vulnerable to Server-Side Request Forgery (SSRF)
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Analysis
by VulDB Data Team • 12/09/2021
The CVE-2021-4075 vulnerability affects the snipe-it asset management system, which is a widely used open-source inventory management solution. This vulnerability manifests as a server-side request forgery flaw that allows remote attackers to make unauthorized requests from the server to internal or external systems. The vulnerability exists within the application's handling of user-supplied input that is used to construct HTTP requests, creating a pathway for attackers to bypass normal access controls and potentially access sensitive internal resources.
The technical implementation of this SSRF vulnerability stems from inadequate validation and sanitization of input parameters that are used to determine the target of HTTP requests within the application's backend processes. When users provide input that gets processed into URLs or endpoints for server-to-server communication, the application fails to properly validate or restrict these inputs, allowing attackers to manipulate the request targets. This flaw typically occurs in applications that use user-provided data to construct URLs for internal services, API calls, or file retrieval operations without sufficient input validation mechanisms.
The operational impact of this vulnerability is significant as it can enable attackers to perform various malicious activities including internal network reconnaissance, access to internal services that should be restricted, data exfiltration, and potentially lateral movement within the network. Attackers can leverage this vulnerability to target internal systems such as databases, internal APIs, or other services that are not directly exposed to the internet but are accessible from the vulnerable server. The vulnerability can also be exploited to perform port scanning of internal networks or to access sensitive data that is protected by network-level access controls.
Organizations using snipe-it should implement immediate mitigations including input validation and sanitization of all user-supplied data that is used in HTTP request construction, implementing strict URL validation to prevent access to internal network resources, and restricting outbound network access from the application server. Network-level controls such as firewalls and access control lists should be configured to limit the application's ability to communicate with internal systems. Additionally, implementing proper application-level restrictions such as allowing only specific domains or IP addresses for outbound requests can significantly reduce the attack surface. This vulnerability aligns with CWE-918 which specifically addresses server-side request forgery and relates to ATT&CK technique T1071.004 for application layer protocol usage in command and control communications.
The vulnerability demonstrates the critical importance of proper input validation and secure coding practices in web applications, particularly those that handle user input for constructing network requests. Organizations should conduct comprehensive security assessments of their web applications to identify similar vulnerabilities and implement defense-in-depth strategies including network segmentation, web application firewalls, and regular security patching. The remediation process should include code reviews to ensure that all user-provided data is properly validated before being used in any network communication contexts, and that the application follows secure coding guidelines to prevent similar issues in future development cycles.