CVE-2021-37144 in CSZ
Summary
by MITRE • 07/30/2021
CSZ CMS 1.2.9 is vulnerable to Arbitrary File Deletion. This occurs in PHP when the unlink() function is called and user input might affect portions of or the whole affected parameter, which represents the path of the file to remove, without sufficient sanitization.
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Analysis
by VulDB Data Team • 08/05/2021
The vulnerability identified as CVE-2021-37144 affects CSZ CMS version 1.2.9 and represents a critical arbitrary file deletion flaw that stems from improper input validation within the PHP application's file handling mechanisms. This vulnerability manifests when the unlink() function is invoked with user-supplied data that directly influences the file path parameter, creating an environment where malicious actors can potentially delete arbitrary files on the target system. The flaw resides in the application's failure to adequately sanitize or validate user input before incorporating it into file system operations, which directly violates fundamental security principles of input validation and privilege separation.
The technical exploitation of this vulnerability occurs when an attacker can manipulate parameters that are subsequently passed to the unlink() function without proper sanitization measures. This creates a path traversal and arbitrary file deletion scenario where an attacker might construct malicious file paths that target critical system files, configuration files, or user data. The vulnerability's impact is amplified by the fact that it operates at the file system level, potentially allowing attackers to remove essential application components, log files, or even system-critical resources. From a cybersecurity perspective, this vulnerability maps directly to CWE-22 (Path Traversal) and CWE-77 (Command Injection) categories, as it enables unauthorized file system manipulation through improperly validated user inputs.
The operational impact of CVE-2021-37144 extends beyond simple data loss, as it can lead to complete application compromise, service disruption, and potential system takeover. An attacker exploiting this vulnerability could systematically remove application files, leading to application instability or complete failure, while also potentially gaining insights into the system's file structure through successful exploitation attempts. This vulnerability particularly affects web applications that handle file management operations and can be exploited through various attack vectors including direct parameter manipulation, file upload functionality, or through other application components that interact with file system operations. The risk is compounded by the fact that many CMS platforms operate with elevated privileges, making successful exploitation potentially devastating to system integrity.
Mitigation strategies for CVE-2021-37144 should focus on implementing robust input validation and sanitization measures, particularly for all user-supplied data that influences file system operations. Organizations should implement strict whitelisting approaches for file paths, employ proper parameter validation before any file system operations, and ensure that all file operations occur within designated safe directories. The implementation of proper access controls and privilege separation mechanisms is crucial, ensuring that applications operate with minimal required permissions. Additionally, regular security updates and patches should be applied immediately upon availability, as this vulnerability affects a specific version of CSZ CMS that likely contains other related security flaws. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1485 (Data Destruction) and T1059 (Command and Scripting Interpreter) where attackers can leverage the arbitrary file deletion capability to disrupt services or escalate privileges through system file manipulation.