Editing Virtual DOS machine (section)

===Security issue===
In January 2010, [[Google]] security researcher [[Tavis Ormandy]] revealed a serious security flaw in Windows NT's VDM implementation that allowed unprivileged users to escalate their privileges to [[Superuser|SYSTEM]] level, noted as applicable to the security of all x86 versions of the Windows NT kernel since 1993. This included all 32-bit versions of Windows NT, 2000, XP, Server 2003, Vista, Server 2008, and Windows 7.<ref name="Microsoft_MS10-015"/> Ormandy published a [[Exploit (computer security)|proof-of-concept exploit]] for the vulnerability.<ref name="Ormandy_2010"/> Prior to Microsoft's release of a security patch, the workaround for this issue was to turn off 16-bit application support, which prevented older programs (those written for DOS and Windows 3.1) from running. 64-bit versions of Windows are not affected since the NTVDM subsystem is not included.<ref name="inquirer"/><ref name="technet"/> Once the Microsoft security patches had been applied to the affected operating systems the VDM could be safely reenabled.<ref group="nb" name="VDMReg"/>