Krebs - Patch Tuesday, August 2018 Edition

Adobe and Microsoft each released security updates for their software on Tuesday. Adobe plugged five security holes in its Flash Player browser plugin. Microsoft pushed 17 updates to fix at least 60 vulnerabilities in Windows and other software, including two “zero-day” flaws that attackers were already exploiting before Microsoft issued patches to fix them.

According to security firm Ivanti, the first of the two zero-day flaws (CVE-2018-8373) is a critical flaw in Internet Explorer that attackers could use to foist malware on IE users who browse to hacked or booby-trapped sites. The other zero-day is a bug (CVE-2018-8414) in the Windows 10 shell that could allow an attacker to run code of his choice.

Microsoft also patched more variants of the Meltdown/Spectre memory vulnerabilities, collectively dubbed “Foreshadow” by a team of researchers who discovered and reported the Intel-based flaws. For more information about how Foreshadow works, check out their academic paper (PDF), and/or the video below. Microsoft’s analysis is here.

One nifty little bug fixed in this patch batch is CVE-2018-8345. It addresses a problem in the way Windows handles shortcut files; ending in the “.lnk” extension, shortcut files are Windows components that link (hence the “lnk” extension) easy-to-recognize icons to specific executable programs, and are typically placed on the user’s Desktop or Start Menu.

That description of a shortcut file was taken verbatim from the first widely read report on what would later be dubbed the Stuxnet worm, which also employed an exploit for a weakness in the way Windows handled shortcut (.lnk) files. According to security firm Qualys, this patch should be prioritized for both workstations and servers, as the user does not need to click the file to exploit. “Simply viewing a malicious LNK file can execute code as the logged-in user,” Qualys’ Jimmy Graham wrote.

Not infrequently, Redmond ships updates that end up causing stability issues for some users, and it doesn’t hurt to wait a day or two before seeing if any major problems are reported with new updates before installing them. Microsoft doesn’t make it easy for Windows 10 users to change this setting, but it is possible. For all other Windows OS users, if you’d rather be alerted to new updates when they’re available so you can choose when to install them, there’s a setting for that in Windows Update.

It’s a good idea to get in the habit of backing up your computer before applying monthly updates from Microsoft. Windows has some built-in tools that can help recover from bad patches, but restoring the system to a backup image taken just before installing updates is often much less hassle and an added piece of mind while you’re sitting there praying for the machine to reboot successfully after patching.

Adobe’s Flash update brings the program to v. 30.0.0.154 for Windows, macOS, Chrome and Linux. Most readers here know how I feel about Flash, which is a major security liability and a frequent target of browser-based attacks. The updates from Microsoft include these Flash fixes for IE, and Google Chrome has already pushed an update to address these five Flash flaws (although a browser restart may be needed).

But seriously, if you don’t have a specific need for Flash, just disable it already. Chrome is set to ask before playing Flash objects, but disabling Flash in Chrome is simple enough. Paste “chrome://settings/content” into a Chrome browser bar and then select “Flash” from the list of items. By default it should be set to “Ask first” before running Flash, although users also can disable Flash entirely here or whitelist and blacklist specific sites.

By default, Mozilla Firefox on Windows computers with Flash installed runs Flash in a “protected mode,” which prompts the user to decide if they want to enable the plugin before Flash content runs on a Web site.

Adobe also released security updates for its PDF Reader and Acrobat products.

As always, please leave a note in the comments below if you experience any problems installing any of these updates.

from Krebs on Security https://krebsonsecurity.com/2018/08/patch-tuesday-august-2018-edition/