CVE-2020-23209 in phpList
Summary
by MITRE • 07/02/2021
A stored cross site scripting (XSS) vulnerability in phplist 3.5.3 allows attackers to execute arbitrary web scripts or HTML via a crafted payload entered into the "List Description" field under the "Edit A List" module.
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Analysis
by VulDB Data Team • 07/09/2021
This stored cross site scripting vulnerability exists within phplist version 3.5.3, specifically within the "List Description" field of the "Edit A List" module. The flaw represents a critical security weakness that enables attackers to inject malicious scripts into the application's database, which are then executed whenever the affected page is accessed by other users. The vulnerability stems from insufficient input validation and output sanitization mechanisms that fail to properly escape or filter user-supplied content before it is stored and subsequently rendered in the web interface. This type of vulnerability falls under the Common Weakness Enumeration category CWE-79, which specifically addresses cross-site scripting flaws where untrusted data is improperly incorporated into web pages without proper sanitization. The attack vector is particularly dangerous because it leverages the application's legitimate functionality to persist malicious code, making it difficult to detect and mitigate through traditional security measures.
The operational impact of this vulnerability extends beyond simple script execution, as it can potentially enable attackers to perform session hijacking, steal sensitive user information, or redirect victims to malicious websites. When an attacker submits crafted HTML or JavaScript code into the List Description field, this content is stored in the database and displayed to any user who views the list information. The stored nature of this vulnerability means that the malicious payload remains active until manually removed from the database, providing attackers with sustained access to victim systems. This weakness can be exploited by attackers who have gained access to the phplist application through other means, such as legitimate administrative credentials, or through phishing attacks targeting system administrators. The vulnerability demonstrates a fundamental flaw in the application's data handling processes, where user input is treated as trusted content without adequate sanitization before being stored and subsequently rendered.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application. Organizations should immediately apply the vendor-provided security patches or upgrade to a patched version of phplist to resolve this vulnerability. Additionally, implementing proper content security policies, input sanitization, and output encoding techniques can help prevent similar issues in the future. The remediation process should include thorough code reviews to identify and address all potential XSS vulnerabilities within the application, particularly in areas where user-generated content is processed and displayed. Security measures should also include regular vulnerability assessments and penetration testing to identify potential injection points that could be exploited by attackers. This vulnerability highlights the importance of following secure coding practices and adhering to the principle of least privilege, ensuring that user inputs are never directly trusted or rendered without proper sanitization. The ATT&CK framework categorizes this type of vulnerability under T1059.005 for command and script injection, emphasizing the need for comprehensive protection against malicious script execution within web applications. Organizations should also implement web application firewalls and monitoring systems to detect and prevent exploitation attempts, while maintaining detailed logging of administrative activities to track potential unauthorized access or modifications to list descriptions.