CVE-2021-40595 in Online Leave Management System
Summary
by MITRE • 01/21/2022
SQL injection vulnerability in Sourcecodester Online Leave Management System v1 by oretnom23, allows attackers to execute arbitrary SQL commands via the username parameter to /leave_system/classes/Login.php.
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Analysis
by VulDB Data Team • 01/27/2022
The CVE-2021-40595 vulnerability represents a critical sql injection flaw within the Sourcecodester Online Leave Management System version 1, developed by oretnom23. This vulnerability exists in the authentication module at the /leave_system/classes/Login.php endpoint where user input is improperly handled. The flaw specifically targets the username parameter which serves as the primary authentication input field. Attackers can exploit this weakness by crafting malicious sql payloads that bypass authentication mechanisms and gain unauthorized access to the system. The vulnerability stems from insufficient input validation and sanitization practices within the application's login processing logic, creating an avenue for malicious actors to manipulate database queries through crafted user inputs.
This sql injection vulnerability operates under the common weakness enumeration CWE-89 which categorizes improper neutralization of special elements used in sql commands. The attack vector specifically targets the username parameter, allowing adversaries to inject malicious sql code that executes within the database context. When the application processes the username input without proper sanitization, the sql query structure becomes vulnerable to manipulation. Attackers can leverage this to extract sensitive data, modify database records, or even escalate privileges within the system. The vulnerability's impact is amplified by the fact that it occurs during the authentication process, potentially allowing unauthorized access to user accounts and administrative functions.
The operational implications of CVE-2021-40595 are severe and multifaceted within the context of leave management systems. Successful exploitation could result in complete database compromise, allowing attackers to view, modify, or delete all leave records, user credentials, and system configurations. The vulnerability could enable attackers to bypass authentication entirely, gaining access to sensitive employee information including personal details, leave balances, and approval workflows. Additionally, the attacker could potentially inject malicious code into the database that persists across system operations, creating long-term security risks. The impact extends beyond simple data theft as the vulnerability could facilitate privilege escalation attacks, leading to full system compromise and potential lateral movement within network environments where such systems operate.
Mitigation strategies for CVE-2021-40595 must address both immediate remediation and long-term security improvements. The primary solution involves implementing proper input validation and parameterized queries throughout the application's codebase, particularly in the login module. Developers should adopt prepared statements or parameterized queries to ensure that user inputs are treated as data rather than executable code. Input sanitization measures including character set validation, length restrictions, and special character filtering should be implemented to prevent malicious payloads from reaching the database layer. Network-level protections such as web application firewalls and intrusion detection systems can provide additional monitoring and blocking capabilities. Regular security audits and code reviews should be conducted to identify and remediate similar vulnerabilities across the entire application stack, ensuring compliance with security standards and best practices established by organizations such as owasp and nist.