CVE-2020-15768 in Gradle
Summary
by MITRE
An issue was discovered in Gradle Enterprise 2017.3 - 2020.2.4 and Gradle Enterprise Build Cache Node 1.0 - 9.2. Unrestricted HTTP header reflection allows remote attackers to obtain authentication cookies (if an XSS issue exists) via the /info/headers, /cache-info/headers, /admin-info/headers, /distribution-broker-info/headers, or /cache-node-info/headers path.
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Analysis
by VulDB Data Team • 09/18/2020
This vulnerability exists in Gradle Enterprise versions ranging from 2017.3 through 2020.2.4 and Gradle Enterprise Build Cache Node versions 1.0 through 9.2, representing a critical security flaw that exposes authentication mechanisms to remote exploitation. The issue stems from unrestricted HTTP header reflection in multiple administrative endpoints, specifically targeting paths including /info/headers, /cache-info/headers, /admin-info/headers, /distribution-broker-info/headers, and /cache-node-info/headers. When an attacker can manipulate HTTP headers through these endpoints, they gain the ability to potentially extract authentication cookies from the server responses, which could enable unauthorized access to protected administrative functions.
The technical flaw manifests as a lack of proper input validation and sanitization within the header reflection mechanism of the Gradle Enterprise administration interface. This vulnerability directly maps to CWE-116, which describes improper encoding or escaping of output, and represents a classic case of information exposure through reflected content. The vulnerability operates under the principle that when an application reflects user-supplied input directly into HTTP headers without proper sanitization, it creates an avenue for attackers to inject malicious content that can be interpreted by client-side components. This particular implementation flaw allows attackers to craft HTTP requests that cause the server to echo back potentially sensitive header information, including authentication tokens that may be present in the headers.
The operational impact of this vulnerability is significant as it provides attackers with a potential pathway to escalate privileges and gain unauthorized access to administrative functions within the Gradle Enterprise environment. The reflected header information could include session cookies, authentication tokens, or other sensitive header data that would normally be protected from direct client access. This vulnerability particularly dangerous in environments where Gradle Enterprise is used for critical build processes, as it could allow attackers to compromise the integrity of the entire build infrastructure. The reflected nature of the vulnerability means that even a simple HTTP request modification could trigger the exposure of authentication data, making it extremely difficult to detect and prevent through traditional network monitoring approaches.
The security implications extend beyond simple information disclosure, as this vulnerability could be leveraged in combination with other attack vectors such as cross-site scripting vulnerabilities that may exist within the same environment. According to ATT&CK framework, this vulnerability aligns with T1566.001, which covers the use of malicious input to gain unauthorized access, and T1071.004, which addresses application layer protocol usage. The reflected header data could potentially be exploited to create persistent access tokens or session hijacking scenarios, particularly if the application does not properly implement secure header practices. Organizations using these vulnerable versions should consider this vulnerability as a potential entry point for broader attacks against their build infrastructure and development environments.
Mitigation strategies should focus on implementing proper input validation and sanitization for all header reflection mechanisms within the affected applications. Organizations should upgrade to patched versions of Gradle Enterprise and Build Cache Node as soon as possible, as these releases would contain the necessary security fixes to prevent header reflection attacks. Additionally, implementing proper header sanitization techniques, such as removing or encoding potentially dangerous characters from reflected headers, would provide defense in depth. Network segmentation and access controls should be strengthened around the affected endpoints, and monitoring should be enhanced to detect unusual header reflection patterns that could indicate exploitation attempts. Regular security assessments of the build infrastructure should include verification of header handling mechanisms to prevent similar vulnerabilities from being introduced in future versions.