CVE-2021-34129 in LaikeTui
Summary
by MITRE • 06/16/2021
LaikeTui 3.5.0 allows remote authenticated users to delete arbitrary files, as demonstrated by deleting install.lock in order to reinstall the product in an attacker-controlled manner. This deletion is possible via directory traversal in the uploadImg, oldpic, or imgurl parameter.
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Analysis
by VulDB Data Team • 06/18/2021
The vulnerability identified as CVE-2021-34129 affects LaikeTui version 3.5.0 and represents a critical directory traversal flaw that enables authenticated remote attackers to perform arbitrary file deletion operations. This vulnerability specifically targets the file upload and image management functionality of the application, creating a pathway for attackers to manipulate the system's file structure beyond intended boundaries. The flaw exists within the processing of three distinct parameters: uploadImg, oldpic, and imgurl, all of which are susceptible to directory traversal attacks that allow attackers to navigate beyond the intended directories and access sensitive system files.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the file handling mechanisms of LaikeTui. When authenticated users submit requests containing maliciously crafted paths in any of the affected parameters, the application fails to properly validate or sanitize the input before processing file operations. This allows attackers to specify directory paths that traverse upward through the file system hierarchy, ultimately gaining access to files outside the intended upload directories. The demonstration of this vulnerability shows attackers exploiting the flaw to delete the install.lock file, which is critical for preventing unauthorized reinstallation of the application, thereby enabling complete system reinstallation under attacker control.
The operational impact of CVE-2021-34129 extends beyond simple file deletion capabilities and represents a severe privilege escalation vector that can lead to complete system compromise. By deleting the install.lock file, attackers can manipulate the application's installation state and potentially execute arbitrary code during reinstallation processes. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks. The vulnerability also aligns with ATT&CK technique T1059.007, which involves command and script injection through file upload mechanisms, and T1484.001, which covers path traversal attacks in web applications.
The security implications of this vulnerability are particularly concerning given that it requires only authenticated access, meaning that attackers who can obtain legitimate user credentials or exploit other authentication bypass mechanisms can immediately leverage this flaw. The affected parameters uploadImg, oldpic, and imgurl are commonly used in web applications for image management and user content handling, making this vulnerability particularly dangerous in environments where user-uploaded content is processed. Organizations running LaikeTui 3.5.0 should consider this vulnerability as a critical threat that could enable attackers to completely compromise the application's integrity and potentially escalate privileges to system-level access.
Mitigation strategies for CVE-2021-34129 should focus on implementing robust input validation and sanitization for all file path parameters, particularly those used in image and file upload operations. The primary fix involves implementing proper path validation that prevents directory traversal sequences such as ..\ or ../ from being processed in file operations. Organizations should also implement strict file access controls and ensure that all file operations are performed within designated safe directories, with no access to system-critical files or directories. Additionally, implementing proper authentication and session management controls, along with regular security audits of file handling mechanisms, will help prevent exploitation of similar vulnerabilities. The fix should be implemented in accordance with security best practices outlined in OWASP Top Ten and NIST guidelines for secure coding practices, specifically addressing the prevention of path traversal attacks and ensuring proper input validation for all user-supplied data.