SB2021030915 - Multiple vulnerabilities in Microsoft Windows Win32k

Description

This security bulletin contains information about 4 secuirty vulnerabilities.

1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-26900)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions in the Windows Win32k, which leads to security restrictions bypass and privilege escalation.

2) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-26863)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions in the Windows Win32k, which leads to security restrictions bypass and privilege escalation.

3) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-26875)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions in the Windows Win32k, which leads to security restrictions bypass and privilege escalation.

4) Untrusted Pointer Dereference (CVE-ID: CVE-2021-27077)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to untrusted pointer dereference in multiple functions within win32kfull.sys driver. A local user can run a specially crafted program to trigger untrusted pointer dereference and execute arbitrary code with SYSTEM privileges.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26900
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26863
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26875
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27077
• https://www.zerodayinitiative.com/advisories/ZDI-21-403/
• https://www.zerodayinitiative.com/advisories/ZDI-21-482/
• https://www.zerodayinitiative.com/advisories/ZDI-21-501/
• https://www.zerodayinitiative.com/advisories/ZDI-21-500/
• https://www.zerodayinitiative.com/advisories/ZDI-21-499/
• https://www.zerodayinitiative.com/advisories/ZDI-21-498/
• https://www.zerodayinitiative.com/advisories/ZDI-21-497/
• https://www.zerodayinitiative.com/advisories/ZDI-21-496/
• https://www.zerodayinitiative.com/advisories/ZDI-21-495/
• https://www.zerodayinitiative.com/advisories/ZDI-21-494/