CVE-2018-7669 in Sitecore.NET
Summary
by MITRE
An issue was discovered in Sitecore Sitecore.NET 8.1 rev. 151207 Hotfix 141178-1 and above. The 'Log Viewer' application is vulnerable to a directory traversal attack, allowing an attacker to access arbitrary files from the host Operating System using a sitecore/shell/default.aspx?xmlcontrol=LogViewerDetails&file= URI. Validation is performed to ensure that the text passed to the 'file' parameter correlates to the correct log file directory. This filter can be bypassed by including a valid log filename and then appending a traditional 'dot dot' style attack.
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Analysis
by VulDB Data Team • 07/04/2024
The vulnerability identified as CVE-2018-7669 represents a critical directory traversal flaw within Sitecore's Log Viewer application, specifically affecting versions 8.1 rev. 141178-1 and later. This security weakness resides in the web application's handling of user-supplied input through the xmlcontrol parameter in the default.aspx page, where the file parameter controls access to log files stored on the server's file system. The flaw enables attackers to bypass the intended file validation mechanism that should restrict access to only legitimate log files within a designated directory structure. The vulnerability stems from inadequate input sanitization and validation processes that fail to properly restrict path traversal sequences, allowing malicious actors to navigate beyond the intended directory boundaries.
The technical implementation of this vulnerability exploits the predictable nature of the Log Viewer's file access control mechanism. When a user requests a log file through the web interface, the application validates that the requested filename corresponds to a legitimate log file within the expected directory. However, this validation process can be circumvented by appending traditional directory traversal sequences such as "../" to the filename parameter. The bypass occurs because the application's filtering logic does not adequately sanitize or normalize the input path, allowing attackers to manipulate the file path to access arbitrary files on the host operating system. This weakness specifically targets the xmlcontrol parameter with the LogViewerDetails control, where the file parameter is directly incorporated into the file system access path without proper canonicalization.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with unrestricted access to the underlying file system of the Sitecore application server. An attacker could potentially access sensitive configuration files, database connection strings, application source code, or other system files that contain confidential information. The vulnerability affects the entire Sitecore application infrastructure since it operates at the web application layer and can be exploited through standard HTTP requests without requiring elevated privileges or specialized tools. The attack vector is particularly concerning because it requires no authentication, making it accessible to any user with access to the Sitecore application's web interface, which could include unauthorized parties who gain access through other means.
Organizations affected by this vulnerability should implement immediate mitigations including input validation at multiple layers of the application stack, proper path normalization and canonicalization, and restriction of file system access to only necessary directories. The most effective immediate fix involves strengthening the validation logic to reject any input containing directory traversal sequences or to properly canonicalize paths before file access operations. Security controls should include implementing a whitelist approach for acceptable file names and paths, rather than relying on blacklisting patterns that can be bypassed. Additionally, organizations should consider implementing web application firewalls to detect and block suspicious path traversal attempts, as well as conducting comprehensive security testing to identify similar vulnerabilities in other application components. This vulnerability aligns with CWE-22 Directory Traversal and follows attack patterns documented in the MITRE ATT&CK framework under the technique of path traversal attacks, specifically targeting the execution of unauthorized file system operations.