CVE-2019-3969 in Comodo
Summary
by MITRE
Comodo Antivirus versions up to 12.0.0.6810 are vulnerable to Local Privilege Escalation due to CmdAgent's handling of COM clients. A local process can bypass the signature check enforced by CmdAgent via process hollowing which can then allow the process to invoke sensitive COM methods in CmdAgent such as writing to the registry with SYSTEM privileges.
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Analysis
by VulDB Data Team • 11/01/2023
The vulnerability identified as CVE-2019-3969 represents a critical local privilege escalation flaw within Comodo Antivirus software versions up to 12.0.0.6810. This vulnerability stems from improper handling of Component Object Model (COM) clients by the CmdAgent service, which operates with elevated privileges to perform antivirus functions. The core issue lies in the service's insufficient validation mechanisms when processing incoming COM requests, creating an exploitable pathway for malicious actors to escalate their privileges from standard user level to system level.
The technical exploitation of this vulnerability relies on process hollowing techniques to bypass the signature verification mechanisms that CmdAgent typically enforces. Process hollowing allows an attacker to inject malicious code into a legitimate process, effectively masking their activities while leveraging the target process's trusted credentials. In this specific case, the attacker can manipulate the CmdAgent service to execute arbitrary code with SYSTEM privileges, despite the normal security restrictions that should prevent such behavior. This technique directly relates to attack patterns documented in the ATT&CK framework under process injection and privilege escalation tactics.
The operational impact of this vulnerability is severe as it allows any local user to gain SYSTEM-level access to the affected system, potentially enabling complete compromise of the machine. Once exploited, attackers can modify system registry entries, install persistent backdoors, manipulate security settings, and access all user data without detection. The vulnerability affects the fundamental security model of the antivirus solution, turning a security tool into a potential attack vector rather than a protective mechanism. This represents a classic case of privilege escalation through service manipulation, where the legitimate system service becomes a conduit for malicious activity.
The underlying flaw corresponds to CWE-269, which addresses improper privilege management in software systems, and CWE-787, concerning out-of-bounds write vulnerabilities that can occur when services improperly validate input parameters. Organizations should immediately update to Comodo Antivirus versions that address this vulnerability, as the exploit requires no network connectivity and can be executed entirely locally. System administrators should also implement additional monitoring for suspicious COM activity and registry modifications, while considering the deployment of privilege monitoring tools to detect unauthorized elevation attempts. The vulnerability highlights the importance of secure service design principles and proper input validation in privileged components, particularly those handling inter-process communication mechanisms that are essential to system security functions.