Without a doubt, May was a bad month for Windows 7 users. The widespread WannaCry ransomware affected computers and machines running Windows 7, while a new bug discovered last week is capable of slowing down and crashing computers running Windows 7, as well as Windows 8.
As strange as it may sound, four characters are enough to trigger this vulnerability, which can slow down your system, or more often, lead to a blue screen of death. So whatever you do, Windows 7 & Windows 8 users (and Vista users, if there are any out there), do not try to open any file with the filename “$MFT”.
This particular filename is typically reserved for special metadata files on the Windows NTFS filesystem, and when you try to open a file that includes these characters as part of the filename or directory path of the file (e.g. C:\$MFT\image) it will crash your computer, according to Ars Technica.
The bug does not appear to affect Windows 10, while Microsoft is already aware of the issue and is pending the release of a corresponding update to fix it.
Many of you may remember one of the most annoying, or for many, amusing, bugs from the Windows 95 and 98 era: specially formatted file names could cause the operating system to crash. Malicious users could exploit this bug to attack other users' machines by using one of the specially formatted file names as image sources. The browser would try to access that file, and Windows would crash.
As it turns out, Windows 7, 8.1 and Vista are affected by a similar type of error.
The Verge successfully tested the bug on a Windows 7 computer with Internet Explorer as the default browser. Using a file name with the path “c:\$MFT\123” in a website image, the test caused a machine to slow down to the point where a restart was required. Some machines may eventually experience a blue screen of death, as the filesystem “locks” on that file and all other applications cannot access the files.
