CVE-2020-9736 in Experience Manager
Summary
by MITRE
AEM versions 6.5.5.0 (and below), 6.4.8.1 (and below), 6.3.3.8 (and below) and 6.2 SP1-CFP20 (and below) are affected by a stored XSS vulnerability that allows users with access to the Content Repository Development Environment to store malicious scripts in certain node fields. These scripts may be executed in a victim’s browser when browsing to the page containing the vulnerable field.
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Analysis
by VulDB Data Team • 11/13/2020
The vulnerability identified as CVE-2020-9736 represents a critical stored cross-site scripting flaw within Adobe Experience Manager platforms. This security weakness affects multiple versions of AEM including 6.5.5.0 and earlier, 6.4.8.1 and earlier, 6.3.3.8 and earlier, and 6.2 SP1-CFP20 and earlier releases. The flaw resides in the Content Repository Development Environment where authenticated users can inject malicious scripts into specific node fields. This vulnerability operates under the Common Weakness Enumeration framework as CWE-79, which specifically addresses Cross-Site Scripting vulnerabilities. The attack vector leverages the privilege of users who have access to the content repository, making it particularly dangerous as it can be exploited by both internal and external attackers who gain legitimate access to these environments.
The technical implementation of this vulnerability allows malicious actors to store JavaScript code within node fields that are subsequently rendered in web pages. When unsuspecting users browse to pages containing these compromised fields, their browsers execute the embedded scripts within the context of their current session. This stored XSS attack occurs because the application fails to properly sanitize or escape user input before rendering it in the browser context. The vulnerability essentially creates a persistent threat where malicious code can be executed repeatedly each time the affected page is accessed, making it a particularly insidious security flaw that can compromise multiple users over time.
The operational impact of CVE-2020-9736 extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities against affected users. The vulnerability can be exploited to steal session cookies, redirect users to phishing sites, deface web content, or even execute more sophisticated attacks such as credential theft or privilege escalation. The attack surface is significant since the vulnerability affects multiple major versions of Adobe Experience Manager, potentially impacting thousands of organizations that rely on these platforms for content management and digital experiences. The stored nature of the vulnerability means that even after the initial injection, the malicious code continues to execute whenever affected pages are accessed, creating a persistent threat that can be difficult to detect and remediate.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to patched versions of Adobe Experience Manager, implementing proper input validation and output encoding mechanisms, and conducting thorough security assessments of all content repository fields. The mitigation strategies should align with the ATT&CK framework's approach to defending against client-side attacks, particularly focusing on the T1059.007 technique related to script injection. Security teams should also establish monitoring protocols to detect unauthorized content modifications and implement web application firewalls to filter malicious payloads. Regular security training for content authors and administrators is crucial to prevent accidental or intentional exploitation of this vulnerability through social engineering or insider threats. The remediation process must include comprehensive testing to ensure that all node fields are properly sanitized and that the patched versions have been correctly deployed across all affected environments.