CVE-2020-9735 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 search queries return the page containing the vulnerable field.
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Analysis
by VulDB Data Team • 11/13/2020
The vulnerability identified as CVE-2020-9735 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 component where authenticated users can inject malicious scripts into specific node fields. This vulnerability operates under the Common Weakness Enumeration category CWE-79 which specifically addresses cross-site scripting flaws, making it a direct descendant of well-known web application security weaknesses that have plagued enterprise content management systems for decades.
The technical execution of this vulnerability occurs through the manipulation of node fields within AEM's repository structure. When legitimate users with appropriate access rights store malicious JavaScript code within these fields, the script becomes persistent within the system's data store. The vulnerability is triggered when search queries return pages containing these compromised fields, causing the malicious code to execute within the victim's browser context. This stored XSS attack vector is particularly dangerous because it leverages the trust relationship between the user and the application, allowing attackers to bypass traditional security measures that might protect against reflected XSS attacks. The attack chain follows the standard pattern of injection, persistence, and execution, with the malicious content being retrieved and rendered when users interact with search results or browse content pages that contain the compromised data.
The operational impact of CVE-2020-9735 extends beyond simple script execution, as it provides attackers with the capability to perform session hijacking, steal sensitive user credentials, redirect victims to malicious sites, or even execute arbitrary commands on behalf of authenticated users. Given that AEM is widely used for enterprise content management and digital experience platforms, the potential for damage is substantial. Attackers could exploit this vulnerability to gain unauthorized access to sensitive corporate data, manipulate content, or establish persistent backdoors within the organization's digital infrastructure. The vulnerability particularly affects organizations that rely heavily on AEM for their web presence and content management, as it provides a direct pathway for attackers to compromise user sessions and potentially escalate privileges within the system. This weakness can be exploited in conjunction with other attacks to create more sophisticated compromise scenarios, making it a significant concern for enterprise security teams managing AEM deployments.
Organizations should implement immediate mitigations including applying the latest security patches from Adobe, which address the specific XSS vulnerability in the affected AEM versions. Network segmentation and proper input validation should be enforced to prevent unauthorized users from storing malicious content within the repository. Web application firewalls should be configured to detect and block suspicious script patterns in HTTP requests, particularly those targeting node fields within the content repository. Access controls must be reviewed and strengthened to ensure that only authorized personnel have write access to critical repository components, implementing the principle of least privilege. Additionally, regular security audits of content repository structures should be conducted to identify and remediate any stored malicious content that may have already been injected. The mitigation strategies should align with ATT&CK framework tactics related to command and control, credential access, and persistence, ensuring that defensive measures address both the immediate vulnerability and potential exploitation patterns that attackers might employ.