CVE-2021-27130 in Online Reviewer System
Summary
by MITRE • 04/14/2021
Online Reviewer System 1.0 contains a SQL injection vulnerability through authentication bypass, which may lead to a reverse shell upload.
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Analysis
by VulDB Data Team • 04/15/2026
The CVE-2021-27130 vulnerability resides within the Online Reviewer System version 1.0, a web-based application designed for managing academic reviews and submissions. This system appears to be a typical academic platform that handles user authentication and content management, making it a potentially attractive target for attackers seeking unauthorized access to academic institutions or research data repositories. The vulnerability manifests as a SQL injection flaw that specifically targets the authentication mechanism, representing a critical security weakness in the system's access control implementation.
The technical flaw in this vulnerability stems from improper input validation and sanitization within the authentication module of the Online Reviewer System. When users attempt to log in, the system fails to properly escape or parameterize user inputs before incorporating them into SQL queries. This allows malicious actors to inject crafted SQL commands through login parameters, potentially bypassing the authentication process entirely. The vulnerability specifically affects the login functionality where user credentials are processed, creating a pathway for attackers to manipulate the underlying database queries. According to CWE classification, this represents a CWE-89: SQL Injection vulnerability, which falls under the broader category of injection flaws that remain among the most prevalent and dangerous web application security weaknesses.
The operational impact of this vulnerability extends far beyond simple authentication bypass, as it creates a direct pathway for attackers to gain unauthorized system access. Once authenticated, an attacker can leverage the compromised account to upload malicious files, including reverse shells that provide remote command execution capabilities. This enables attackers to establish persistent access to the system, potentially leading to data exfiltration, system compromise, or use as a staging ground for further attacks against the broader network. The implications are particularly severe for academic institutions where such systems may contain sensitive research data, personal information of students and faculty, or intellectual property. From an ATT&CK framework perspective, this vulnerability maps to T1190: Exploit Public-Facing Application and T1078: Valid Accounts, as it allows adversaries to leverage the application's authentication mechanism to gain system access.
Mitigation strategies for CVE-2021-27130 require immediate attention through multiple defensive layers. The primary fix involves implementing proper input validation and parameterized queries throughout the authentication system, ensuring that all user inputs are properly sanitized before database interaction. Organizations should deploy web application firewalls to detect and block malicious SQL injection attempts, while also implementing robust logging and monitoring to detect unauthorized access attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other system components. Additionally, implementing multi-factor authentication and least privilege access controls can significantly reduce the impact of any successful exploitation attempts. System administrators should also ensure that the Online Reviewer System is regularly updated with the latest security patches and that proper access controls are implemented to limit the damage that could occur if the vulnerability is exploited. The remediation process should include comprehensive code review to identify any other potential injection points within the application's codebase.