CVE-2017-2150 in Calendar
Summary
by MITRE
Directory traversal vulnerability in Booking Calendar version 7.0 and earlier allows remote attackers to read arbitrary files via specially crafted captcha_chalange parameter.
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Analysis
by VulDB Data Team • 05/23/2020
The directory traversal vulnerability identified as CVE-2017-2150 affects the Booking Calendar plugin version 7.0 and earlier, presenting a critical security risk that enables remote attackers to access arbitrary files on the target system. This vulnerability specifically manifests through the captcha_chalange parameter, which fails to properly validate user input before processing file operations. The flaw represents a classic path traversal attack vector that exploits insufficient input sanitization mechanisms within the plugin's file handling routines.
The technical implementation of this vulnerability stems from improper validation of the captcha_chalange parameter which is used to generate challenge responses for CAPTCHA verification. When attackers submit malicious input containing directory traversal sequences such as ../ or ..\, the plugin fails to sanitize these inputs before using them in file system operations. This allows adversaries to navigate outside the intended directory structure and access sensitive files that should remain protected. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The flaw demonstrates a clear lack of input validation and proper file access controls within the plugin's authentication and verification mechanisms.
Operationally, this vulnerability poses significant risks to systems running affected Booking Calendar versions, as it enables attackers to potentially access configuration files, database credentials, user data, and other sensitive information stored on the server. Remote exploitation requires no authentication and can be executed through web-based interfaces, making it particularly dangerous for publicly accessible web applications. The impact extends beyond simple file reading, as successful exploitation may lead to complete system compromise through information disclosure, privilege escalation, or further attack vectors. Attackers could leverage this vulnerability to extract database connection strings, administrative credentials, or other sensitive configuration data that could facilitate additional attacks against the system or network.
Mitigation strategies for CVE-2017-2150 should prioritize immediate patching of the Booking Calendar plugin to version 7.1 or later, which contains the necessary fixes for the directory traversal vulnerability. Organizations should implement input validation measures that sanitize all user-supplied parameters before processing, particularly those used in file system operations. The implementation of proper access controls and least privilege principles can help minimize the potential impact of such vulnerabilities. Security monitoring should include detection of suspicious file access patterns and directory traversal attempts within web application logs. Additionally, organizations should consider implementing web application firewalls and input validation rules that specifically target path traversal sequences to provide defense-in-depth protection against similar vulnerabilities. This vulnerability demonstrates the critical importance of proper input validation and access control implementation in web applications, aligning with ATT&CK technique T1059.007 for path traversal attacks and highlighting the need for comprehensive security controls throughout the software development lifecycle.