CVE-2018-17341 in BigTree
Summary
by MITRE
BigTree 4.2.23 on Windows, when Advanced or Simple Rewrite routing is enabled, allows remote attackers to bypass authentication via a ..\ substring, as demonstrated by a launch.php?bigtree_htaccess_url=admin/images/..\ URI.
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Analysis
by VulDB Data Team • 05/17/2023
The vulnerability CVE-2018-17341 affects BigTree CMS version 4.2.23 running on Windows systems with either Advanced or Simple Rewrite routing enabled. This authentication bypass flaw stems from improper input validation and path traversal handling within the application's URL processing mechanism. The vulnerability specifically exploits how the system handles directory traversal sequences, allowing remote attackers to manipulate URI parameters to access restricted administrative resources without proper authentication credentials.
The technical implementation of this vulnerability involves the manipulation of the bigtree_htaccess_url parameter in the launch.php script. When attackers include the ..\ substring in the URI path, the application fails to properly sanitize or validate the input, enabling path traversal attacks. The ..\ sequence allows attackers to navigate up directory levels and access files outside the intended web root directory. This particular attack vector leverages the administrative images directory path, demonstrating how the vulnerability can be exploited to gain unauthorized access to administrative functions. The flaw exists because the application does not adequately implement input sanitization or path validation controls, particularly when Advanced or Simple Rewrite routing modes are active.
The operational impact of this vulnerability is severe as it provides remote attackers with unauthorized administrative access to the BigTree CMS system. Successful exploitation allows attackers to bypass authentication mechanisms entirely and gain full administrative privileges, potentially leading to complete system compromise, data exfiltration, modification of critical system files, and unauthorized access to sensitive information. The vulnerability affects Windows installations specifically, suggesting that the path traversal handling may differ between operating systems, potentially due to different file system handling or web server configurations. The fact that this issue occurs with both Advanced and Simple Rewrite routing modes indicates that the vulnerability is deeply embedded in the core URL routing and path resolution logic rather than being a configuration-specific issue.
This vulnerability aligns with CWE-22 Path Traversal and CWE-287 Improper Authentication categories, representing a classic directory traversal attack that bypasses authentication controls. From an ATT&CK framework perspective, this maps to T1078 Valid Accounts for privilege escalation and T1566 Phishing for credential theft, as attackers can use this vulnerability to gain administrative access without needing legitimate credentials. The attack surface is particularly concerning as it requires no prior authentication and can be exploited remotely, making it a high-severity issue that could lead to complete system compromise. Organizations using BigTree CMS on Windows systems with rewrite routing enabled should immediately implement mitigations to address this vulnerability.
Mitigation strategies include applying the vendor-provided patches or updates that address the path traversal vulnerability in the URL handling mechanism. Administrators should disable Advanced or Simple Rewrite routing modes if they are not essential for the application's functionality, as these modes appear to be the trigger for the vulnerability. Input validation should be strengthened to reject or sanitize directory traversal sequences such as ..\, and the application should implement proper path normalization and validation checks. Network-level protections such as web application firewalls can help detect and block suspicious URI patterns containing directory traversal sequences. Additionally, implementing principle of least privilege access controls and monitoring for unusual administrative access patterns can help detect exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other applications and systems within the organization's infrastructure.