CVE-2019-18211 in C1 CMS
Summary
by MITRE
An issue was discovered in Orckestra C1 CMS through 6.6. The EntityTokenSerializer class in Composite.dll is prone to unvalidated deserialization of wrapped BinaryFormatter payloads, leading to arbitrary remote code execution for any low-privilege user.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2019-18211 affects Orckestra C1 CMS versions through 6.6 and represents a critical security flaw in the EntityTokenSerializer class within the Composite.dll assembly. This issue stems from the improper handling of serialized data that employs the BinaryFormatter serialization mechanism, which has been widely recognized as inherently insecure due to its susceptibility to deserialization attacks. The vulnerability allows any low-privilege user to exploit this weakness and achieve arbitrary remote code execution on the affected system, fundamentally undermining the security posture of the CMS platform.
The technical root cause of this vulnerability lies in the insecure deserialization practices implemented within the EntityTokenSerializer class. BinaryFormatter, despite its convenience for serializing complex objects, has been deprecated by Microsoft and marked as insecure due to its ability to execute arbitrary code during the deserialization process. When the system processes serialized tokens containing malicious payloads, the BinaryFormatter deserializes these objects without proper validation or sanitization, creating an attack surface where crafted serialized data can trigger code execution. This flaw directly maps to CWE-502 which catalogs deserialization of untrusted data as a critical security weakness, specifically targeting the dangerous nature of BinaryFormatter usage in enterprise applications.
The operational impact of this vulnerability is severe and far-reaching for organizations utilizing Orckestra C1 CMS. Any user with minimal privileges can potentially leverage this vulnerability to execute arbitrary commands on the server, effectively bypassing authentication and authorization mechanisms. Attackers could use this capability to escalate privileges, install backdoors, exfiltrate sensitive data, or compromise the entire application infrastructure. The remote execution aspect means that attackers do not require physical access or elevated privileges to exploit this vulnerability, making it particularly dangerous in web-facing applications where user access is common. This vulnerability essentially transforms any legitimate user account into a potential attack vector for full system compromise.
Organizations affected by this vulnerability should immediately implement mitigations including patching to the latest version of Orckestra C1 CMS where the issue has been resolved. The recommended approach involves replacing BinaryFormatter usage with safer serialization alternatives such as JSON.NET or other secure serialization mechanisms that do not execute code during deserialization. Additionally, network segmentation and access controls should be enforced to limit user access and reduce the attack surface. Security monitoring should be enhanced to detect unusual deserialization patterns, and regular security assessments should be conducted to identify similar vulnerabilities in other components of the application stack. The ATT&CK framework categorizes this type of vulnerability under T1203 - Exploitation for Client Execution and T1059 - Command and Scripting Interpreter, highlighting the multi-stage nature of exploitation that begins with deserialization and progresses to command execution. Organizations should also consider implementing runtime application self-protection mechanisms and code integrity checks to prevent exploitation of similar vulnerabilities in the future, as the underlying issue reflects broader patterns of insecure deserialization practices that continue to plague enterprise applications.