CVE-2021-40719 in Connect Server
Summary
by MITRE • 10/22/2021
Adobe Connect version 11.2.2 (and earlier) is affected by a Deserialization of Untrusted Data vulnerability to achieve arbitrary method invocation when AMF messages are deserialized on an Adobe Connect server. An attacker can leverage this to execute remote code execution on the server.
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Analysis
by VulDB Data Team • 10/28/2021
Adobe Connect version 11.2.2 and earlier implementations contain a critical deserialization vulnerability classified as CVE-2021-40719 that stems from improper handling of Action Message Format AMF data during server-side processing. This vulnerability represents a direct violation of the CWE-502 security principle, which specifically addresses the dangerous practice of deserializing untrusted data without proper validation. The flaw exists within the server's AMF message handling mechanism where incoming serialized data is automatically processed without sufficient sanitization checks, creating an attack surface that allows malicious actors to inject arbitrary method calls through crafted AMF payloads.
The technical exploitation of this vulnerability occurs when the Adobe Connect server receives and processes AMF messages containing maliciously constructed serialized objects. During the deserialization process, the server attempts to reconstruct objects from the serialized data, but due to the lack of proper input validation, attacker-controlled method invocations can be executed within the server's execution context. This creates a remote code execution vector that bypasses normal access controls and can potentially allow full system compromise. The vulnerability aligns with ATT&CK technique T1059.007 for remote code execution through application layer protocols, specifically targeting the Action Message Format protocol used by Adobe Connect.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can lead to complete system compromise, data exfiltration, and potential lateral movement within network environments. Attackers can leverage this vulnerability to establish persistent access, deploy additional malware, or use the compromised server as a launch point for further attacks against other network resources. The attack surface is particularly concerning given that Adobe Connect is commonly used in enterprise environments for web conferencing and collaboration, making it a valuable target for threat actors seeking to gain unauthorized access to sensitive corporate information. Organizations running affected versions face significant risk of unauthorized access and potential data breaches, with the vulnerability potentially affecting thousands of systems across multiple organizations. The remediation strategy requires immediate patching of affected Adobe Connect installations to version 11.2.3 or later, along with network segmentation and monitoring to detect potential exploitation attempts.
This vulnerability demonstrates the critical importance of proper input validation and secure deserialization practices in enterprise software implementations. The flaw represents a fundamental security weakness that could have been prevented through adherence to secure coding practices and proper sanitization of all external input data. Organizations should implement comprehensive security controls including network monitoring, intrusion detection systems, and regular vulnerability assessments to identify and remediate similar vulnerabilities across their technology infrastructure. The incident highlights the necessity of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against sophisticated exploitation techniques that target common software frameworks and protocols.