CVE-2021-44534 in ExpressionEngine
Summary
by MITRE • 05/31/2024
Insufficient user input filtering leads to arbitrary file read by non-authenticated attacker, which results in sensitive information disclosure.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/31/2024
This vulnerability represents a critical security flaw in web applications that fail to properly validate and sanitize user input before processing file operations. The issue stems from inadequate filtering mechanisms that allow attackers to manipulate file path parameters and access files outside of intended directories. The vulnerability is classified as a path traversal or directory traversal attack vector that enables unauthorized information disclosure without requiring authentication credentials. Such flaws typically occur when applications directly use user-supplied input to construct file paths without proper validation or sanitization. The weakness creates an opportunity for attackers to navigate the file system and retrieve sensitive data including configuration files, database credentials, application source code, and other confidential information.
The technical implementation of this vulnerability involves the exploitation of insufficient input validation in file handling functions. Attackers can craft malicious input strings that contain sequences like ../ or ..\ to traverse directory structures and access files that should remain protected. When the application processes these inputs without proper sanitization, it can inadvertently read files from arbitrary locations on the server filesystem. This type of vulnerability is particularly dangerous because it can be exploited by unauthenticated users who do not require valid credentials to access sensitive data. The flaw often manifests in applications that dynamically construct file paths based on user input without proper access control or path validation mechanisms in place.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially compromise entire system security postures. Successful exploitation can lead to exposure of database connection strings, cryptographic keys, application configuration files, and other sensitive data that could enable further attacks. Attackers might gain insights into system architecture, application logic, and potential attack vectors that could facilitate more sophisticated exploitation attempts. The vulnerability can result in data breaches, compliance violations, and significant reputational damage to organizations. From an attack perspective, this weakness aligns with techniques documented in the attack pattern taxonomy under the MITRE ATT&CK framework for privilege escalation and credential access. The vulnerability also corresponds to CWE-22 which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal.
Mitigation strategies for this vulnerability require comprehensive input validation and sanitization mechanisms that prevent malicious path manipulation attempts. Organizations should implement strict access control measures that enforce proper directory boundaries and validate all file path inputs against expected patterns. The implementation of secure coding practices including the use of whitelisting approaches, proper file access controls, and input sanitization routines can effectively prevent exploitation. Additionally, organizations should deploy web application firewalls and intrusion detection systems that can identify and block suspicious path traversal attempts. Regular security testing including automated vulnerability scanning and manual penetration testing should be conducted to identify and remediate similar weaknesses throughout the application lifecycle. The remediation process should follow established security frameworks such as the OWASP Top Ten and NIST cybersecurity guidelines to ensure comprehensive protection against path traversal vulnerabilities.