Microsoft issues emergency Windows patch — install this right now

Woman in yellow top clapping hand to forehead while holding laptop.
(Image credit: Roman Samborskyi/Shutterstock)

Microsoft issued an emergency Windows security update yesterday (Aug. 19) to correct two remote-access flaws that could let hackers take over your PC.

But before you go rushing to install the update, check your operating system. The flaws being fixed affect only Windows 8.1 and the corresponding server version, Windows Service 2012 R2. They may also affect Windows 8 and Windows 7, but Microsoft no longer supports those and isn't providing any fixes for them.

In Windows 10, the flaws were fixed with last week's Patch Tuesday updates. It's not clear why Patch Tuesday didn't take care of the issue on Windows 8.1.

To exploit either of these flaws, an attacker would need to already have a foothold on the targeted machine,  such as through malware or phishing. These two flaws, both in the Windows Remote Access feature, would let the attacker then "escalate privileges," or gain system powers to fully control the machine.

You'll need to go to this specific page on the Microsoft Update Catalog website to manually download and install the updates. Make sure to choose the correct version for your operating system: There's one for 32-bit machines, i.e. "x86-based systems," and another for 64-bit machines, or "x64-based systems." 

You won't need to restart your PC once you've downloaded and installed the appropriate patch.

How to check your system version

To find out whether you're running a 32-bit or 64-bit version of Windows, the procedures vary a bit by operating system, as detailed here

In Windows 8 and 8.1, you'll need to open the Settings menu by either swiping in from the right edge of the screen on a touchscreen, or by pointing to the lower-right corner of the screen with your mouse pointer and dragging the pointer up. 

Then tap or click Change PC Settings, select PC and Devices, then PC Info in the left-hand navigation bar, and you'll see the information under System Type in the right-hand screen.

In Windows 10, right-click the Windows icon in the bottom left of the screen, select Settings, select System, scroll down to About in the left-hand navigation bar and select it, and then check System Type under Device Specifications in the right-hand windows.

In Windows 7, click the Start button at the bottom left corner, type Computer in the search box that pops up, right-click on Computer and select Properties. A new window will pop up; the system version will be under the Windows Edition tab.

Hat tip to Bleeping Computer.

Paul Wagenseil

Paul Wagenseil is a senior editor at Tom's Guide focused on security and privacy. He has also been a dishwasher, fry cook, long-haul driver, code monkey and video editor. He's been rooting around in the information-security space for more than 15 years at, SecurityNewsDaily, TechNewsDaily and Tom's Guide, has presented talks at the ShmooCon, DerbyCon and BSides Las Vegas hacker conferences, shown up in random TV news spots and even moderated a panel discussion at the CEDIA home-technology conference. You can follow his rants on Twitter at @snd_wagenseil.