Horizon Alert
Summary of the vulnerability and why it matters
This vulnerability exists within the Microsoft Windows kernel when 16-bit applications are enabled on 32-bit systems. Improper validation of certain BIOS calls allows local users to elevate their privileges by manipulating specific data structures and triggering an exception within the Windows Virtual DOS Machine subsystem. This flaw could enable unauthorized access and control over the affected systems.
- Vulnerable Windows kernel component
- Flaw in BIOS call validation
- Local privilege escalation possible
Attack Path
How an attacker could exploit the issue
This vulnerability allows a local attacker to elevate privileges on affected Microsoft Windows systems. Exploitation requires the system to have access to 16-bit applications enabled on a 32-bit x86 platform. An attacker can craft a specific data structure and then trigger a Windows Virtual DOS Machine subsystem call. This can lead to improperly handled exceptions within the Windows kernel, granting the attacker elevated control.
- Local access required for exposure.
- Attacker crafts data structure and calls function.
- Results in kernel exception and privilege escalation.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability allows local users to gain elevated privileges on affected Windows systems. Attackers can exploit this by crafting a specific data structure and initiating the Windows Virtual DOS Machine subsystem. Successful exploitation could lead to unauthorized access and control over the system, posing a significant business risk.
- Attacker skill level: High
- Required access or conditions: Local access, 16-bit application support enabled
- Business risk or urgency: High
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability allows local users to escalate privileges on affected Windows systems by exploiting an exception handler flaw within the Windows kernel. The impact on organizations includes the potential for unauthorized access to sensitive data and system compromise, increasing the overall business risk. The exploit requires local access and the enablement of 16-bit application support on 32-bit x86 platforms.
- Identify all systems with 16-bit application support enabled.
- Restrict or disable 16-bit application support where not essential.
- Apply vendor security updates and validate their successful implementation.
