CVE-2020-9741 in Experience Manager
Summary
by MITRE
The AEM forms add-on for versions 6.5.5.0 (and below) and 6.4.8.2 (and below) is affected by a stored XSS vulnerability that allows users with 'Author' privileges to store malicious scripts in fields associated with the Forms component. These scripts may be executed in a victim’s browser when they open the page containing the vulnerable field.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/13/2020
The vulnerability identified as CVE-2020-9741 represents a critical stored cross-site scripting flaw within Adobe Experience Manager forms add-on components. This security weakness affects specific versions of AEM including 6.5.5.0 and earlier releases, as well as 6.4.8.2 and earlier versions, creating a significant attack surface for malicious actors targeting content management systems. The flaw specifically exploits the forms component functionality where user input is not properly sanitized before being stored and subsequently rendered back to users, creating a persistent XSS vector that can be leveraged for various malicious purposes.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding mechanisms within the AEM forms add-on module. When users with 'Author' privileges create or modify form fields, the system fails to adequately sanitize the submitted content, allowing malicious script payloads to be stored directly within the form field data. This stored content is then executed in the browser context of any user who views the page containing the vulnerable form component, regardless of whether they possess administrative privileges or are simply browsing the published content. The vulnerability operates at the application layer and specifically targets the web interface rendering engine that processes form data for display purposes.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and data exfiltration. An attacker with 'Author' privileges can craft malicious scripts that persist in the system and execute against unsuspecting users who access the affected pages, potentially compromising user sessions and gaining unauthorized access to sensitive information. The attack requires minimal privileges to exploit, making it particularly dangerous as it can be leveraged by individuals with relatively low-level access permissions within the content management system. This vulnerability directly maps to CWE-79 which describes improper neutralization of input during web page generation, and aligns with ATT&CK technique T1566.001 for initial access through malicious content.
Organizations affected by this vulnerability should immediately implement several mitigation strategies to protect their systems. The primary recommendation involves upgrading to patched versions of AEM that address this specific XSS vulnerability, as Adobe has released updates to resolve the issue. Additionally, administrators should implement strict input validation and output encoding policies within the AEM environment to prevent malicious script injection. Network segmentation and privileged access controls should be enforced to limit the potential impact of compromised author accounts. Regular security assessments and monitoring of form component usage should be conducted to identify and remediate any potential exploitation attempts. The vulnerability also highlights the importance of principle of least privilege implementation where users should only be granted necessary permissions to minimize the attack surface available to potential adversaries.