CVE-2021-41563 in Tad Book3
Summary
by MITRE • 10/08/2021
Tad Book3 editing book function does not filter special characters. Unauthenticated attackers can remotely inject JavaScript syntax and execute stored XSS attacks.
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Analysis
by VulDB Data Team • 10/14/2021
The vulnerability identified as CVE-2021-41563 resides within the Tad Book3 editing book function, representing a critical security flaw that undermines the application's input validation mechanisms. This weakness specifically manifests in the book editing functionality where the system fails to properly sanitize user inputs, particularly when processing special characters that could be exploited for malicious purposes. The absence of adequate filtering allows attackers to inject potentially harmful code without requiring any authentication credentials, making this vulnerability particularly dangerous as it can be exploited by anyone with access to the affected system.
The technical nature of this flaw aligns with CWE-79, which describes Cross-Site Scripting (XSS) vulnerabilities occurring when web applications fail to properly validate or escape user-supplied data before incorporating it into dynamically generated web pages. This particular implementation defect enables unauthenticated remote attackers to perform stored XSS attacks by injecting JavaScript syntax directly into the book editing interface. The vulnerability operates at the application layer where user inputs are processed and stored within the system's database, creating a persistent threat vector that can affect all users who subsequently view the compromised content.
The operational impact of CVE-2021-41563 extends beyond simple data corruption or display issues, as it provides attackers with the capability to execute arbitrary JavaScript code within the context of other users' browsers. This stored XSS vulnerability can be leveraged to steal session cookies, redirect users to malicious websites, deface the application interface, or even perform actions on behalf of authenticated users. The implications are severe as attackers can establish persistent footholds within the application environment, potentially leading to further compromise of user accounts, data exfiltration, or the establishment of backdoor access points. The vulnerability affects the integrity and confidentiality of the entire system, as compromised user sessions can be exploited to gain unauthorized access to sensitive information.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application's data processing pipeline. The primary defense involves sanitizing all user inputs through proper encoding techniques such as HTML entity encoding, JavaScript escaping, and implementing Content Security Policy (CSP) headers to limit the execution of unauthorized scripts. Organizations should also consider implementing web application firewalls that can detect and block suspicious input patterns, while regularly auditing input validation routines to ensure comprehensive coverage. Additionally, the principle of least privilege should be enforced by limiting the types of characters and code that can be submitted through the editing interface, and implementing proper session management controls to prevent exploitation of stolen credentials. The remediation process should include thorough code reviews and penetration testing to identify similar vulnerabilities within the application's broader codebase, ensuring that all user input handling mechanisms are properly secured against XSS attacks.