CVE-2021-40637 in openSIS Classic
Summary
by MITRE • 03/03/2022
OS4ED openSIS 8.0 is affected by cross-site scripting (XSS) in EmailCheckOthers.php. An attacker can inject JavaScript code to get the user's cookie and take over the working session of user.
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Analysis
by VulDB Data Team • 03/06/2022
The vulnerability identified as CVE-2021-40637 affects OS4ED openSIS version 8.0, specifically within the EmailCheckOthers.php component. This represents a critical cross-site scripting flaw that allows remote attackers to inject malicious JavaScript code into the application's web interface. The vulnerability stems from inadequate input validation and output encoding mechanisms within the email checking functionality, creating an avenue for attackers to execute arbitrary code within the context of a victim's browser session.
This XSS vulnerability operates under CWE-79 which classifies it as a weakness in input validation and output encoding. The flaw enables attackers to inject malicious scripts that can capture user cookies, session tokens, and other sensitive information. When a victim visits a maliciously crafted URL or interacts with the vulnerable page, the injected JavaScript executes in their browser, potentially allowing full session hijacking. The attack can be executed through various vectors including email links, form submissions, or direct URL manipulation, making it particularly dangerous in educational environments where users may interact with multiple web applications.
The operational impact of this vulnerability extends beyond simple session theft, as it can enable attackers to perform actions on behalf of authenticated users within the openSIS system. This includes accessing sensitive student data, modifying records, creating new user accounts, or executing administrative functions. The vulnerability is particularly concerning in educational institutions where openSIS typically manages confidential student information, academic records, and personal data. The attack chain follows typical ATT&CK techniques for credential access and privilege escalation through web application exploitation, potentially leading to complete system compromise if attackers can leverage the stolen sessions to access additional systems.
Mitigation strategies should include immediate implementation of proper input sanitization and output encoding mechanisms within the EmailCheckOthers.php file. The application should employ Content Security Policy (CSP) headers to prevent unauthorized script execution, implement proper HTML escaping for all user-controllable data, and utilize secure session management practices including secure cookie attributes and session timeout mechanisms. Additionally, regular security code reviews should be conducted to identify and remediate similar vulnerabilities across the application codebase. Organizations should also implement web application firewalls and monitoring systems to detect and prevent exploitation attempts, while ensuring that all users are educated about the risks of clicking suspicious links or visiting untrusted websites that might contain malicious payloads designed to exploit this vulnerability.