Zero-day vulnerability in Windows

Security restrictions bypass
CVE-2021-31199

Vulnerability details

Advisory: SB2021060830 - Privilege escalation in Microsoft Enhanced Cryptographic Provider

Vulnerable component: Windows

CVE-ID: CVE-2021-31199

CVSSv3 score: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:H/RL:O/RC:C

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Description:

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

The vulnerability exists due to improperly imposed security restrictions in Microsoft Enhanced Cryptographic Provider. A local user can bypass implemented security restrictions and read or modify otherwise restricted information.

Note, the vulnerability is being actively exploited in the wild and related to a zero-day vulnerability in Adobe Reader #VU53125 (CVE-2021-28550) patched on May 11.

External links:

https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2021-31199

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.