CVE-2021-37271 in UEditor
Summary
by MITRE • 09/29/2021
Cross Site Scripting (XSS) vulnerability exists in UEditor v1.4.3.3, which can be exploited by an attacker to obtain user cookie information.
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Analysis
by VulDB Data Team • 10/03/2021
The Cross Site Scripting vulnerability identified as CVE-2021-37271 affects UEditor version 1.4.3.3, representing a critical security flaw that enables attackers to execute malicious scripts within the context of a victim's browser session. This vulnerability stems from inadequate input validation and output encoding mechanisms within the rich text editor component, creating an exploitable vector for malicious code injection. The flaw specifically manifests when user-supplied content containing malicious script tags is processed and rendered without proper sanitization, allowing attackers to craft payloads that can compromise user sessions and extract sensitive information.
The technical implementation of this XSS vulnerability involves the failure to properly sanitize user input before rendering it within the web application interface. UEditor's processing pipeline does not adequately filter or encode special characters and script tags that could be embedded within content submitted by users. This weakness creates a persistent cross site scripting attack surface where an attacker can inject malicious javascript code through the editor's input fields. The vulnerability operates at the client-side execution level, leveraging the browser's trust in the application's legitimate content to execute unauthorized scripts that can access and transmit user session cookies.
The operational impact of this vulnerability extends beyond simple script execution to include comprehensive session hijacking capabilities and potential privilege escalation. Attackers can exploit this flaw to steal user authentication cookies, enabling them to impersonate legitimate users and gain unauthorized access to sensitive data and application functionalities. The vulnerability also poses risks to data integrity and confidentiality, as malicious scripts can capture keystrokes, redirect users to phishing sites, or exfiltrate sensitive information from the victim's browser environment. This creates a significant threat to user privacy and application security, particularly in environments where the editor handles sensitive content or user-generated material.
Mitigation strategies for CVE-2021-37271 should prioritize immediate patching of the UEditor component to the latest secure version that addresses the input validation and output encoding deficiencies. Organizations must implement comprehensive input sanitization measures including the use of Content Security Policy headers, proper HTML encoding of all user-generated content, and the implementation of a whitelist-based approach for acceptable input characters. The vulnerability aligns with CWE-79 which specifically addresses cross site scripting flaws, and follows ATT&CK technique T1531 for credential access through web application attacks. Additional defensive measures include regular security assessments of web applications, implementation of web application firewalls, and user education regarding the risks of interacting with untrusted content. Organizations should also consider implementing session management best practices including secure cookie attributes, session timeout mechanisms, and regular session invalidation procedures to minimize the impact of potential exploitation attempts.