A serious zero-day vulnerability is threatening the security of Windows users. Google has recently disclosed this under attack zero-day in Windows Kernel that awaits a fix.
Windows Kernel Zero-Day Under Attack
Researchers from Google Project Zero have discovered a serious security flaw affecting Windows systems. They have identified this bug in Windows Kernel as a zero-day since it is already under exploitation in the wild.
As revealed via a bug report, the researchers, Mateusz Jurczyk and Sergei Glazunov, identified the flaw that allows elevated privileges to an attacker, thereby allowing the adversary to execute code on the target device.
The Windows Kernel Cryptography Driver (cng.sys) exposes a \Device\CNG device to user-mode programs and supports a variety of IOCTLs with non-trivial input structures. It constitutes a locally accessible attack surface that can be exploited for privilege escalation (such as sandbox escape).
While the researchers tested the exploit on Windows 10, they believe that the bug exists since Windows 7. It means all users with their devices running on Windows 7 to the latest builds of Windows 10 are vulnerable to exploitation.
As disclosed by Ben Hawkes via a tweet, this bug (CVE-2020-17087) can become serious when exploited together with the Chrome zero-day (CVE-2020-15999) disclosed last week.
In addition to last week's Chrome/freetype 0day (CVE-2020-15999), Project Zero also detected and reported the Windows kernel bug (CVE-2020-17087) that was used for a sandbox escape. The technical details of CVE-2020-17087 are now available here: https://t.co/bO451188Mk
— Ben Hawkes (@benhawkes) October 30, 2020
Patch To Arrive Soon
Google researchers discovered the vulnerability around the same time when the
FreeType zero-day in Chrome surfaced online. Specifically, they discovered the on October 22, 2020. Also, they found evidence of the active exploitation of the flaw. Hence, they reported the vulnerability to Microsoft with a 7-day disclosure period. As elaborated in their bug report,
We have evidence that this bug is being used in the wild. Therefore, this bug is subject to a 7 day disclosure deadline.
Eventually, they disclosed the vulnerability after the deadline, even though it still awaits a fix.
However, they have confirmed that a fix will be available by November 10, 2020.