Late spring and early summer in the cybersecurity world were marked by multiple Windows exploits, thanks to the efforts of the controversial hacker figure Nightmare Eclipse. One of the better-known exploits is BlueHammer, a race condition in Windows Defender that gets you a shell with access to the SYSTEM user with just a small script — in other words, the keys to the kingdom in exchange for a double-click. Microsoft released a patch on April 14, but as a clear illustration of the lack of cybersecurity awareness, CISA (the U.S. cyber-defense agency) yesterday marked BlueHammer as actively exploited in ransomware campaigns.
That marks about a month and a half since the patch, and it illustrates quite clearly that when it comes to computer security, the publication of a patch is almost always the easy part; getting that patch into every device that needs it is the real tricky bit. The patch is part of standard Windows updates, too, so there's really no technical reason for not installing it. Additionally, since BlueHammer gets the attackers a SYSTEM shell, the ransomware in question may encrypt parts of the OS or the boot process rather than "just" the data files, potentially making machines unusable on top.
