CVE-2021-20689 in Yomi-Search
Summary
by MITRE • 04/07/2021
Cross-site scripting vulnerability in Yomi-Search Ver4.22 allows remote attackers to inject an arbitrary script via unspecified vectors.
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Analysis
by VulDB Data Team • 04/11/2021
The CVE-2021-20689 vulnerability represents a critical cross-site scripting flaw identified in Yomi-Search version 4.22, exposing systems to remote code execution risks through malicious script injection. This vulnerability falls under the category of input validation failures that permit unauthorized attackers to manipulate application behavior by injecting malicious payloads into web interfaces. The unspecified vectors suggest that multiple entry points within the application may be susceptible to this particular attack pattern, making the vulnerability particularly concerning for comprehensive security assessments.
This XSS vulnerability operates by allowing remote attackers to inject arbitrary scripts into the application's web interface without proper sanitization or validation of user input. The flaw enables attackers to execute malicious code within the context of other users' browsers, potentially leading to session hijacking, credential theft, or unauthorized data manipulation. The vulnerability's classification aligns with CWE-79 which specifically addresses Cross-Site Scripting flaws in web applications, where insufficient input validation creates opportunities for attackers to inject malicious scripts that execute in the victim's browser context. The attack vector typically involves manipulating parameters or form fields that are not properly escaped or validated before being rendered back to users.
The operational impact of this vulnerability extends beyond simple script execution, as it can facilitate more sophisticated attacks including session fixation, data exfiltration, and privilege escalation within the application's user context. Attackers can leverage this vulnerability to impersonate legitimate users, access sensitive information, or modify application data. The remote nature of the attack means that exploitation does not require physical access to the system, making it particularly dangerous for web-based applications that serve multiple users. According to ATT&CK framework, this vulnerability maps to T1566.001 which covers Social Engineering through spearphishing with a malicious attachment or link, where the XSS payload serves as the malicious component that triggers user interaction.
Mitigation strategies for CVE-2021-20689 should prioritize immediate patching of the Yomi-Search application to the latest version that addresses this specific vulnerability. Organizations should implement comprehensive input validation and output encoding mechanisms to prevent script injection attempts, ensuring that all user-provided data is properly sanitized before processing. The implementation of Content Security Policy (CSP) headers can provide an additional layer of protection by restricting script execution sources and preventing unauthorized code injection. Security teams should also conduct thorough code reviews focusing on input handling, implement web application firewalls to detect and block suspicious payloads, and establish monitoring protocols to identify potential exploitation attempts. Regular security assessments and penetration testing should be conducted to verify that all input vectors have been properly secured and that the application maintains robust defenses against similar vulnerabilities. The vulnerability's presence in version 4.22 indicates that organizations using this specific release should urgently upgrade to patched versions while implementing compensating controls to reduce attack surface exposure.