CVE-2020-28141 in Online Discussion Forum
Summary
by MITRE • 04/19/2021
The messaging subsystem in the Online Discussion Forum 1.0 is vulnerable to XSS in the message body. An authenticated user can send messages to arbitrary users on the system that include javascript that will execute when viewing the messages page.
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Analysis
by VulDB Data Team • 04/28/2021
The vulnerability identified as CVE-2020-28141 resides within the messaging subsystem of Online Discussion Forum version 1.0, representing a critical cross-site scripting flaw that undermines the platform's security posture. This vulnerability specifically affects the message body field where user input is not properly sanitized or validated before being rendered to other users. The flaw enables authenticated attackers to inject malicious javascript code into message content that executes when other users view the messages page, creating a persistent threat vector within the forum environment.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding mechanisms within the forum's message handling system. When an authenticated user submits a message containing javascript payload, the application fails to properly escape or filter special characters that could be interpreted as executable code by web browsers. This occurs because the system does not implement proper sanitization of user-supplied content before rendering it in the browser context, allowing attackers to inject malicious scripts that execute in the victim's browser session. The vulnerability is classified as a classic reflected cross-site scripting issue with persistent characteristics, as the malicious code is stored on the server and executed whenever affected pages are accessed.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it provides attackers with the capability to perform session hijacking, redirect users to malicious sites, or harvest sensitive information from authenticated sessions. An attacker with valid credentials can craft messages that execute scripts in the context of other users' browsers, potentially allowing unauthorized access to private communications, user accounts, or sensitive forum data. The persistent nature of the vulnerability means that once a malicious message is posted, it continues to affect all users who view the affected pages until the message is removed by administrators. This creates ongoing risk for forum participants and undermines the trust in the platform's security mechanisms, particularly affecting users who rely on the forum for sensitive discussions or collaborative work.
Mitigation strategies for this vulnerability should include immediate implementation of proper input sanitization and output encoding measures to prevent javascript execution in user-generated content. The forum should implement comprehensive content security policies that filter or escape all potentially dangerous characters and script tags from user inputs. Security controls should be enhanced through the adoption of established frameworks such as the OWASP Secure Coding Practices, which recommend strict input validation and output encoding for all user-supplied data. Additionally, the system should implement proper access controls and monitoring to detect suspicious message patterns, while regular security audits should be conducted to identify similar vulnerabilities in other components of the messaging infrastructure. The implementation of these controls aligns with ATT&CK framework techniques related to credential access and defense evasion, ensuring comprehensive protection against exploitation of this vulnerability.