Patch Tuesday Lowdown, April 2019 Edition
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2019-0803 +1 in the same advisory: …0859 | Local Privilege Escalation in Microsoft Win32k Kernel Component CVE-2019-0803 is a privilege escalation flaw in Microsoft's Win32k kernel component caused by improper handling of objects in memory. It is triggered locally when code already running on a Windows system reaches the vulnerable Win32k object-handling path, allowing memory corruption that the attacker can leverage. Successful exploitation lets the attacker run arbitrary code in kernel mode, elevating from a low-privileged account to full system-level control. Per the available data, the affected component is Microsoft Win32k across Windows installations, though specific affected Windows versions and builds are not enumerated in the source data and should be confirmed against Microsoft's advisory. Exploitation is confirmed in the wild: CISA added it to the KEV catalog on 2021-11-03 with known ransomware use, and EPSS assigns a 45.2% probability of exploitation within 30 days (99th percentile). Do: Apply Microsoft Windows security updates per vendor instructions — this flaw was fixed in Microsoft's April 2019 security updates, so ensure systems are running those or later cumulative updates and verify by checking OS build numbers. Prioritize patching endpoints and servers where untrusted or low-privileged users can execute code, given documented ransomware chaining. Treat KEV status as a deadline: systems unpatched for this Win32k flaw should be considered actively targeted. | 7.8 | 45% | KEV ransomware |
| masshundreds of millions of Windows desktops and servers (Win32k is a core component shipped with essentially all Windows installations) |
Full article590 words · extracted from krebsonsecurity.com · click to collapse
Microsoft today released fifteen software updates to fix more than 70 unique security vulnerabilities in various flavors of its Windows operating systems and supported software, including at least two zero-day bugs. These patches apply to Windows, Internet Explorer (IE) and Edge browsers, Office, Sharepoint and Exchange. Separately, Adobe has issued security updates for Acrobat/Reader and Flash Player.
According to security firm Rapid 7, two of the vulnerabilities — CVE-2019-0803 and CVE-2019-0859 — are already being exploited in the wild. They can result in unauthorized elevation of privilege, and affect all supported versions of Windows.
“An attacker must already have local access to an affected system to use these to gain kernel-level code execution capabilities,” Rapid7 researcher Greg Wiseman observed. “However, one of the 32 Remote Code Execution (RCE) vulnerabilities patched today could potentially be used with them in an exploit chain to obtain full control of a system.”
Aside from these zero-day privilege escalation flaws, Wiseman said, it’s a fairly standard Patch Tuesday.
“Which of course still means that there are bugs that should be patched as soon as possible, such as the eight vulnerabilities classified as critical in the scripting engine used by Microsoft browsers, and CVE-2019-0822 (an RCE in Microsoft Office that can be exploited by convincing a user to open a malicious file).”
Adobe’s Patch Tuesday includes security updates for its Flash Player and AIR software, as well as Adobe Reader and Acrobat.
Flash updates are installed along with other monthly Windows patch rollups for consumers, and auto-installed by Google Chrome, but users may need to reboot the operating system (in the case of IE/Edge) or the browser (in Chrome) for the new updates to take effect.
Adobe’s actions also sound the death knell for Adobe Shockwave Player, which has at long last reached end-of-life.
That means no more security updates for Shockwave, which has always been something of an ugly stepchild to Flash. That is to say, Shockwave never really got the security attention Flash has received but nevertheless has been just as vulnerable and often lagging months or years behind Flash in terms of updates.
Chris Goettl, director of product management and security for security firm Ivanti, said Windows users need to get any existing Shockwave installations out of their environments now.
“There are 7 vulnerabilities that are going to be vulnerable for the majority of Shockwave installs still in existence,” Goettl said. “You can bet an exploit is imminent there.”
Standard advice: Staying up-to-date on Windows patches is good. Updating only after you’ve backed up your important data and files is even better. A good backup means you’re not pulling your hair out if the odd buggy patch causes problems booting the system.
Windows 10 likes to install patches all in one go and reboot your computer on its own schedule. 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.
As always, if you experience any problems installing any of these patches this month, please feel free to leave a comment about it below; there’s a good chance other readers have experienced the same and may even chime in here with some helpful tips.
Further reading:
Text extracted automatically; images, tables and formatting may be missing. Original: https://krebsonsecurity.com/2019/04/patch-tuesday-lowdown-april-2019-edition/