Apple macOS: information disclosure flaw under attack

What is affected

Apple macOS is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

macOS Monterey contains an out-of-bounds read vulnerability that could allow an application to read kernel memory.

What an attacker can do

This is a information disclosure flaw. It lets an attacker read data they are not supposed to see, such as memory contents, credentials or internal files. It is often the first step of a larger attack.

How it is reached

Needs access to the device or a file opened on it

Access the attacker needs

A basic user account

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. Update Apple macOS now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply updates per vendor instructions.

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on April 4, 2022, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by April 25, 2022, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 1.1% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 65% of all scored vulnerabilities.

Its CVSS severity score is 5.5 out of 10 (medium), as recorded in the US National Vulnerability Database.

Technical description

An out-of-bounds read issue existed that led to the disclosure of kernel memory. This was addressed with improved input validation. This issue is fixed in macOS Monterey 12.3.1, Security Update 2022-004 Catalina, macOS Big Sur 11.6.6. A local user may be able to read kernel memory.