Privilege escalation in Microsoft Enhanced Cryptographic Provider

Published: 2021-06-08

Risk	Medium
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2021-31199 CVE-2021-31201
CWE-ID	CWE-264
Exploitation vector	Local
Public exploit	Vulnerability #1 is being exploited in the wild. Vulnerability #2 is being exploited in the wild.
Vulnerable software Subscribe	Windows Operating systems & Components / Operating system Windows Server Operating systems & Components / Operating system
Vendor	Microsoft

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Security restrictions bypass

EUVDB-ID: #VU53909

Risk: Medium

CVSSv3.1: 4.2 [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]

CVE-ID: CVE-2021-31199

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

Exploit availability: No

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.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Windows: 7 - 10 2004

Windows Server: 2008 - 2019 2004

External links

http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31199

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.

2) Security restrictions bypass

EUVDB-ID: #VU53910