CVE-2023-37243 in Agent Package Availability
Summary
by MITRE • 10/31/2023
The C:\Windows\Temp\Agent.Package.Availability\Agent.Package.Availability.exe file is automatically launched as SYSTEM when the system reboots. Since the C:\Windows\Temp\Agent.Package.Availability folder inherits permissions from C:\Windows\Temp and Agent.Package.Availability.exe is susceptible to DLL hijacking, standard users can write a malicious DLL to it and elevate their privileges.
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Analysis
by VulDB Data Team • 09/05/2024
This vulnerability represents a critical privilege escalation flaw in Windows systems that leverages insecure temporary directory permissions and DLL hijacking techniques. The issue stems from the automatic execution of Agent.Package.Availability.exe with SYSTEM privileges during system reboot processes, creating a persistent attack vector that standard users can exploit to gain elevated access. The vulnerability specifically targets the C:\Windows\Temp\Agent.Package.Availability directory structure, which inherits permissions from the broader C:\Windows\Temp folder, allowing unauthorized users to manipulate the execution environment.
The technical exploitation mechanism relies on the principle of DLL hijacking where malicious code can be loaded into the legitimate process through improperly configured search paths. When Agent.Package.Availability.exe executes during reboot, it searches for required dynamic link libraries in predictable locations including the directory containing the executable itself. Since the parent Temp directory allows write access to standard users, attackers can place malicious DLL files in the target directory, which will then be loaded and executed with SYSTEM privileges. This represents a classic case of insecure directory permissions combined with predictable execution paths that violates fundamental security principles.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with persistent SYSTEM-level access that can be maintained across system reboots. The automatic execution during reboot ensures that the malicious DLL will be loaded every time the system starts, creating a stealthy persistence mechanism that is difficult to detect through standard monitoring approaches. This vulnerability directly maps to CWE-427 Uncontrolled Search Path Element and CWE-787 Out-of-bounds Write, while also aligning with ATT&CK technique T1068 Exploitation for Privilege Escalation and T1543 Create or Modify System Process. The attack surface is particularly concerning because it operates at the system level without requiring user interaction or specialized tools beyond basic file manipulation capabilities.
Mitigation strategies must address both the immediate permission issues and the underlying architectural flaws in the system design. Organizations should immediately restrict write permissions on the C:\Windows\Temp directory and its subdirectories to prevent unauthorized DLL placement, while also implementing proper access controls for the Agent.Package.Availability.exe file itself. The recommended approach includes establishing more restrictive permissions for the Temp directory structure, implementing strict DLL loading policies through AppLocker or similar application control mechanisms, and conducting thorough security audits of all auto-executing processes. Additionally, system administrators should implement monitoring for unauthorized file modifications in system directories and establish regular vulnerability assessments to identify similar permission misconfigurations that could create analogous attack vectors.