CVE-2018-18253 in Access Manager
Summary
by MITRE
An issue was discovered in CapMon Access Manager 5.4.1.1005. CALRunElevated.exe attempts to enforce access control by adding an unprivileged user to the local Administrators group for a very short time to execute a single command. However, the user is left in that group if the command crashes, and there is also a race condition in all cases.
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Analysis
by VulDB Data Team • 08/01/2023
The vulnerability identified as CVE-2018-18253 resides within CapMon Access Manager version 5.4.1.1005, specifically within the CALRunElevated.exe component that handles privilege escalation operations. This flaw represents a critical access control bypass mechanism that fundamentally undermines the security model of the application. The component is designed to temporarily elevate user privileges by adding unprivileged accounts to the local Administrators group, execute a single administrative command, and then remove the user from that group. However, the implementation contains a fundamental design flaw that creates persistent privilege escalation opportunities.
The technical implementation of this vulnerability stems from a race condition and improper privilege cleanup mechanism. When CALRunElevated.exe executes a command, it temporarily grants administrative privileges to the user account through group membership modification. The flaw occurs because the system fails to properly clean up the elevated privileges in all execution paths, particularly when command execution fails or crashes. This race condition creates a window where the user remains elevated even after the intended command should have completed, effectively maintaining administrative access indefinitely. The vulnerability manifests due to inadequate error handling and privilege management, where the system does not properly validate that the elevated privilege removal occurs regardless of execution outcome.
The operational impact of this vulnerability is severe and far-reaching within environments where CapMon Access Manager is deployed. An attacker who can trigger the vulnerable code path can maintain administrative access to systems for extended periods, potentially leading to complete system compromise. This persistent elevation of privileges allows for data exfiltration, lateral movement, and establishment of persistence mechanisms. The vulnerability affects both local and network-based attack scenarios, as the elevated privileges can be leveraged to access system resources, modify configurations, and execute arbitrary code. The race condition aspect means that timing attacks or process manipulation could be employed to extend the duration of elevated access beyond normal operational parameters.
Mitigation strategies for CVE-2018-18253 require immediate attention and comprehensive remediation approaches. Organizations should prioritize patching the CapMon Access Manager to the latest version that addresses this privilege escalation flaw. In the interim, administrators should implement strict monitoring of group membership changes and privilege escalation events through security information and event management systems. The principle of least privilege should be enforced by limiting the scope of accounts that can trigger elevated operations and implementing additional authentication layers. System administrators should also consider disabling the vulnerable CALRunElevated.exe functionality entirely if it is not essential for operations. This vulnerability aligns with CWE-284, which addresses improper access control, and maps to ATT&CK technique T1068, which covers local privilege escalation through race conditions. Organizations should also implement process monitoring to detect unauthorized privilege modifications and establish incident response procedures specifically addressing persistent privilege escalation scenarios.