CVE-2019-16897 in Antivirus Premium
Summary
by MITRE
In K7 Antivirus Premium 16.0.xxx through 16.0.0120; K7 Total Security 16.0.xxx through 16.0.0120; and K7 Ultimate Security 16.0.xxx through 16.0.0120, the module K7TSHlpr.dll improperly validates the administrative privileges of the user, allowing arbitrary registry writes in the K7AVOptn.dll module to facilitate escalation of privileges via inter-process communication with a service process.
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Analysis
by VulDB Data Team • 01/29/2024
The vulnerability identified as CVE-2019-16897 represents a critical privilege escalation flaw affecting multiple K7 security products including Premium, Total Security, and Ultimate Security versions. This issue stems from improper validation of administrative privileges within the K7TSHlpr.dll module, which creates a dangerous condition where unprivileged users can manipulate registry entries through the K7AVOptn.dll module. The flaw specifically manifests through inter-process communication mechanisms that allow malicious actors to communicate with service processes and manipulate system registry settings.
The technical implementation of this vulnerability follows a well-defined pattern that aligns with common privilege escalation techniques documented in the CWE taxonomy under CWE-276. The core issue lies in the insufficient privilege checking mechanism within the K7TSHlpr.dll component, which fails to properly verify whether the calling process possesses administrative rights before allowing registry modifications. This weakness creates a direct pathway for privilege escalation as the service process continues to trust the unverified administrative status of the calling entity. The vulnerability exploits the trust relationship between the user-mode application and the kernel-mode service component, allowing malicious code to write to protected registry locations that should only be accessible to administrators.
From an operational perspective, this vulnerability presents a significant threat to system security as it enables any local user to escalate their privileges to SYSTEM level access. The impact extends beyond simple privilege elevation since the registry modifications can be leveraged to install persistent backdoors, modify security settings, or disable critical system protections. Attackers can exploit this flaw to gain complete control over affected systems without requiring prior administrative access, making it particularly dangerous in enterprise environments where users may have standard privileges but need to run security software. The vulnerability affects a wide range of K7 products, indicating a systemic design flaw rather than an isolated incident, which increases the potential attack surface and impact.
The mitigation strategies for this vulnerability involve immediate patching of affected K7 security products to address the privilege validation logic in K7TSHlpr.dll. System administrators should also implement monitoring for unauthorized registry modifications and establish strict access controls for registry entries related to security software. Organizations should consider implementing the principle of least privilege and regularly audit service accounts to ensure they maintain appropriate permissions. The vulnerability demonstrates the importance of proper privilege validation in inter-process communication scenarios, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploit. Additionally, this issue highlights the need for secure coding practices in security software development, particularly around privilege checking and inter-process communication mechanisms, as outlined in various secure coding standards and best practices.