CVE-2021-40712 in Experience Manager
Summary
by MITRE • 09/28/2021
Adobe Experience Manager version 6.5.9.0 (and earlier) is affected by a improper input validation vulnerability via the path parameter. An authenticated attacker can send a malformed POST request to achieve server-side denial of service.
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Analysis
by VulDB Data Team • 10/03/2021
Adobe Experience Manager version 6.5.9.0 and earlier versions contain an improper input validation vulnerability that manifests through the path parameter handling within the application's server-side processing logic. This weakness allows an authenticated attacker to craft and submit malicious POST requests containing malformed path parameters that can trigger unexpected behavior in the underlying system. The vulnerability resides in the application's insufficient validation mechanisms for user-supplied input, specifically targeting the path parameter that is commonly used for navigation and resource access within the content management framework. According to CWE-20, this represents a classic input validation flaw where the application fails to properly sanitize or validate incoming data before processing it, creating an avenue for malicious actors to exploit the system's processing routines.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can potentially enable more sophisticated attacks depending on the broader system architecture and the attacker's privileges. When an authenticated user submits a malformed request, the server processes the invalid path parameter through its internal routing and resource resolution mechanisms, causing the system to either consume excessive computational resources, enter an error state, or potentially crash the service entirely. This server-side denial of service condition directly impacts the availability of the Adobe Experience Manager service, disrupting legitimate user access and content management operations. The vulnerability's exploitation requires authentication, which means it cannot be leveraged by unauthenticated attackers, but it does represent a significant risk within environments where privileged accounts may be compromised or where insider threats exist.
The technical exploitation of this vulnerability follows patterns consistent with the ATT&CK framework's privilege escalation and denial of service tactics. Attackers can leverage their authenticated access to craft specifically designed POST requests that bypass normal input validation checks, potentially causing the server to process malformed paths in ways that exhaust system resources or trigger critical processing errors. This type of vulnerability often stems from inadequate sanitization of user input before it is processed by the application's internal path resolution logic, which typically involves parsing, validating, and normalizing path strings before accessing corresponding filesystem or database resources. The affected Adobe Experience Manager versions lack proper bounds checking and input sanitization for the path parameter, allowing maliciously crafted values to propagate through the system's processing pipeline without adequate protection mechanisms.
Organizations should implement immediate mitigations including upgrading to Adobe Experience Manager version 6.5.10.0 or later, which contains the necessary patches to address this input validation weakness. Network-level controls such as web application firewalls can provide additional protection by filtering suspicious POST requests and monitoring for patterns consistent with this vulnerability exploitation. Configuration hardening measures should include implementing stricter input validation rules for path parameters, establishing rate limiting mechanisms to prevent abuse of the vulnerable endpoint, and monitoring system logs for unusual patterns of request processing that might indicate exploitation attempts. Security teams should also conduct thorough vulnerability assessments to identify any other potentially affected components within their Adobe Experience Manager deployments and ensure that proper access controls and authentication mechanisms remain in place to limit the scope of potential exploitation.