CVE-2017-14037 in CrushFTP
Summary
by MITRE
CrushFTP before 7.8.0 and 8.x before 8.2.0 has an HTTP header vulnerability.
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Analysis
by VulDB Data Team • 11/12/2019
The vulnerability identified as CVE-2017-14037 affects CrushFTP servers running versions prior to 7.8.0 and 8.x prior to 8.2.0, representing a critical HTTP header manipulation flaw that could enable attackers to bypass authentication mechanisms and gain unauthorized access to sensitive resources. This vulnerability resides in the server's handling of HTTP headers, specifically in how it processes and validates incoming header values during the authentication process. The flaw allows malicious actors to manipulate HTTP headers in ways that circumvent normal security controls, potentially leading to complete system compromise.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within CrushFTP's HTTP request processing pipeline. When the server receives HTTP requests, it fails to properly validate or sanitize certain header fields, creating opportunities for header injection attacks. This weakness falls under the CWE-74 category of Improper Neutralization of Special Elements in Output Used by a Downstream Component, specifically manifesting as HTTP header injection. The vulnerability enables attackers to inject malicious header values that can be interpreted by the application as legitimate authentication credentials or bypass mechanisms, effectively undermining the security model of the FTP server.
From an operational perspective, this vulnerability poses significant risks to organizations relying on CrushFTP for file transfer operations, particularly those handling sensitive data or requiring strict access controls. Attackers exploiting this vulnerability could potentially access restricted directories, download or upload unauthorized files, modify existing content, or even execute arbitrary commands on the server. The impact extends beyond simple unauthorized access as the vulnerability could enable privilege escalation attacks, allowing attackers to assume administrative roles within the FTP environment. This threat vector aligns with ATT&CK technique T1210 - Exploitation of Remote Services, where adversaries leverage weaknesses in network services to gain unauthorized access.
The exploitation of this vulnerability typically involves crafting malicious HTTP requests with specially formatted headers that manipulate the server's authentication logic. Security professionals should note that this vulnerability can be particularly dangerous in environments where CrushFTP serves as a gateway for file transfers between different security domains, as it could enable lateral movement attacks. The vulnerability affects both the 7.x and 8.x release branches, indicating it was present across multiple versions and likely resulted from a fundamental flaw in the HTTP header processing implementation rather than a one-time coding error.
Organizations should prioritize immediate patching of affected CrushFTP installations to address this vulnerability, as the window for exploitation remains open for systems running vulnerable versions. The recommended mitigation strategy includes upgrading to CrushFTP version 7.8.0 or 8.2.0, depending on the current installation, while implementing additional network-level controls such as web application firewalls that can detect and block malicious header injection attempts. Security monitoring should focus on anomalous HTTP header patterns and unusual authentication attempts that could indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper input validation in web applications and the potential for seemingly minor implementation flaws to create significant security risks in network services.