Title: Microsoft Windows Kernel Virtual DOS Machine Privilege Escalation Vulnerability
Severity: HIGH
Description:
The Microsoft Virtual DOS Machine (VDM) is a protected environment that emulates MS-DOS on Windows NT-based operating systems. This issue is caused by an access-validation error. A local attacker can exploit this vulnerability to gain elevated privileges on a vulnerable computer.
The operating system component used to handle VDM may allow the attacker to gain access to protected kernel memory. Certain functions fail to validate system structures, allowing an unauthorized user-space application to access kernel memory.
The vulnerability is present in the Windows kernel code that handles and executes 16-bit code inside a VDM. Windows 16-bit DOS emulation code uses invalid opcode byte sequences to pass requests to the 32-bit VDM code. These invalid sequences are handled by the interrupt 06h (#UD) handler in NTOSKRNL.EXE. The interrupt handler handles the invalid sequence depending on the control word specified in the two bytes before the sequence. If the control word value is not 4250h or 4350h, the invalid sequence is relayed to the process hosting the VDM. The sequences are transmitted to user memory space by the NTVDM.EXE process. The attacker can influence the flow of execution as context structures are swapped out from user memory space to the VDM.
The vulnerability arises because the kernel fails to validate the memory address of the executing code when an invalid sequence is encountered. Since this occurs in user memory space while retaining kernel privileges, an attacker can redirect execution to malicious code. This code executes with kernel-level privileges.
A successful attack can allow the local attacker to gain complete access to the vulnerable computer.
Affected Products:
- Avaya DefinityOne Media Servers
- Avaya DefinityOne Media Servers R10
- Avaya DefinityOne Media Servers R11
- Avaya DefinityOne Media Servers R12
- Avaya DefinityOne Media Servers R6
- Avaya DefinityOne Media Servers R7
- Avaya DefinityOne Media Servers R8
- Avaya DefinityOne Media Servers R9
- Avaya IP600 Media Servers
- Avaya IP600 Media Servers R10
- Avaya IP600 Media Servers R11
- Avaya IP600 Media Servers R12
- Avaya IP600 Media Servers R6
- Avaya IP600 Media Servers R7
- Avaya IP600 Media Servers R8
- Avaya IP600 Media Servers R9
- Avaya Modular Messaging (MSS) 1.1.0
- Avaya Modular Messaging (MSS) 2.0.0
- Avaya S3400 Message Application Server
- Avaya S8100 Media Servers
- Avaya S8100 Media Servers R10
- Avaya S8100 Media Servers R11
- Avaya S8100 Media Servers R12
- Avaya S8100 Media Servers R6
- Avaya S8100 Media Servers R7
- Avaya S8100 Media Servers R8
- Avaya S8100 Media Servers R9
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Advanced Server SP1
- Microsoft Windows 2000 Advanced Server SP2
- Microsoft Windows 2000 Advanced Server SP3
- Microsoft Windows 2000 Advanced Server SP4
- Microsoft Windows 2000 Datacenter Server
- Microsoft Windows 2000 Datacenter Server SP1
- Microsoft Windows 2000 Datacenter Server SP2
- Microsoft Windows 2000 Datacenter Server SP3
- Microsoft Windows 2000 Datacenter Server SP4
- Microsoft Windows 2000 Professional
- Microsoft Windows 2000 Professional SP1
- Microsoft Windows 2000 Professional SP2
- Microsoft Windows 2000 Professional SP3
- Microsoft Windows 2000 Professional SP4
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Server SP1
- Microsoft Windows 2000 Server SP2
- Microsoft Windows 2000 Server SP3
- Microsoft Windows 2000 Server SP4
- Microsoft Windows 2000 Terminal Services
- Microsoft Windows 2000 Terminal Services SP1
- Microsoft Windows 2000 Terminal Services SP2
- Microsoft Windows NT Enterprise Server 4.0
- Microsoft Windows NT Enterprise Server 4.0 SP1
- Microsoft Windows NT Enterprise Server 4.0 SP2
- Microsoft Windows NT Enterprise Server 4.0 SP3
- Microsoft Windows NT Enterprise Server 4.0 SP4
- Microsoft Windows NT Enterprise Server 4.0 SP5
- Microsoft Windows NT Enterprise Server 4.0 SP6
- Microsoft Windows NT Enterprise Server 4.0 SP6a
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Server 4.0 SP1
- Microsoft Windows NT Server 4.0 SP2
- Microsoft Windows NT Server 4.0 SP3
- Microsoft Windows NT Server 4.0 SP4
- Microsoft Windows NT Server 4.0 SP5
- Microsoft Windows NT Server 4.0 SP6
- Microsoft Windows NT Server 4.0 SP6a
- Microsoft Windows NT Terminal Server 4.0
- Microsoft Windows NT Terminal Server 4.0 SP1
- Microsoft Windows NT Terminal Server 4.0 SP2
- Microsoft Windows NT Terminal Server 4.0 SP3
- Microsoft Windows NT Terminal Server 4.0 SP4
- Microsoft Windows NT Terminal Server 4.0 SP5
- Microsoft Windows NT Terminal Server 4.0 SP6
- Microsoft Windows NT Terminal Server 4.0 SP6a
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Workstation 4.0 SP1
- Microsoft Windows NT Workstation 4.0 SP2
- Microsoft Windows NT Workstation 4.0 SP3
- Microsoft Windows NT Workstation 4.0 SP4
- Microsoft Windows NT Workstation 4.0 SP5
- Microsoft Windows NT Workstation 4.0 SP6
- Microsoft Windows NT Workstation 4.0 SP6a
- Microsoft Windows Server 2003 Datacenter x64 Edition
- Microsoft Windows Server 2003 Enterprise x64 Edition
- Microsoft Windows Server 2003 Standard x64 Edition
- Microsoft Windows XP 64-bit Edition
- Microsoft Windows XP 64-bit Edition SP1
- Microsoft Windows XP 64-bit Edition Version 2003
- Microsoft Windows XP 64-bit Edition Version 2003 SP1
- Microsoft Windows XP Home
- Microsoft Windows XP Home SP1
- Microsoft Windows XP Professional
- Microsoft Windows XP Professional SP1
References:
- CORE Security: Windows NTVDM bop exploit
- Microsoft: Microsoft Security Bulletin MS04-032
- eEye Digital Security: Windows VDM #UD Local Privilege Escalation
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