CVE-2018-9117 in WireMock
Summary
by MITRE
WireMock before 2.16.0 contains a vulnerability that allows a remote unauthenticated attacker to access local files beyond the application directory via a specially crafted XML request, aka Directory Traversal.
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Analysis
by VulDB Data Team • 01/18/2020
The vulnerability identified as CVE-2018-9117 affects WireMock versions prior to 2.16.0 and represents a critical directory traversal flaw that enables remote attackers to access arbitrary local files on the server. This vulnerability specifically manifests through XML request handling where an attacker can craft malicious requests that bypass normal file access restrictions. The flaw exists in the application's XML parsing and file resolution mechanisms, allowing unauthorized access to files outside the intended application directory boundaries. The vulnerability is particularly concerning because it requires no authentication credentials, making it exploitable by any remote attacker who can send crafted requests to the WireMock server.
The technical implementation of this vulnerability stems from insufficient input validation and path sanitization within the XML request processing pipeline. When WireMock receives an XML request containing file references, the application fails to properly validate or sanitize the file paths before attempting to resolve them. This allows attackers to use directory traversal sequences such as ../ or ..\ to navigate outside the application's designated working directory and access sensitive files on the underlying filesystem. The vulnerability is classified under CWE-22 which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw demonstrates a fundamental weakness in the application's security architecture where input validation occurs too late in the processing chain, allowing malicious paths to be processed before proper access controls are enforced.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially compromise the entire server environment. Attackers can access configuration files, database credentials, application source code, and other sensitive data that may be stored on the same filesystem as the WireMock service. In containerized environments or when WireMock runs with elevated privileges, the attack surface expands significantly as attackers might gain access to host system files or other containerized applications. The vulnerability affects both development and production environments where WireMock is used for API mocking and testing purposes, creating a potential backdoor for attackers to escalate their privileges and access additional systems. According to ATT&CK framework, this vulnerability maps to T1083 (File and Directory Discovery) and T1566 (Phishing for Information) as attackers can use the discovered information to plan further attacks. The impact is particularly severe in environments where WireMock is deployed with default configurations or where the application directory contains sensitive data, as the vulnerability can expose complete system reconnaissance capabilities to unauthenticated attackers.
The recommended mitigation strategy involves upgrading to WireMock version 2.16.0 or later, which includes proper input validation and path sanitization mechanisms. Organizations should also implement network-level restrictions to limit access to WireMock endpoints, particularly in production environments where the service is not required. Additional security measures include deploying the application in restricted directories with minimal file permissions, implementing proper network segmentation, and monitoring for suspicious file access patterns. Security teams should also consider implementing web application firewalls that can detect and block directory traversal attempts, and conduct regular security assessments to identify similar vulnerabilities in other applications. The vulnerability serves as a reminder of the critical importance of input validation and proper access control mechanisms in all application components, particularly those handling file system operations. Organizations should also review their overall security posture and ensure that all applications follow secure coding practices to prevent similar path traversal vulnerabilities from being introduced in the future.