Zero-day vulnerability in Windows

Buffer overflow
CVE-2018-8120

The vulnerability was reported by ESET in March 2018. The attackers used this vulnerability along with double free error in Adobe Acrobat CVE-2018-4990.

Known malware:

Win32/Exploit.CVE-2018-8120.A trojan (ESET)

Vulnerability details

Advisory: SB2018050813 - Privilege escalation in Microsoft Windows win32k.sys driver

Vulnerable component: Windows

CVE-ID: CVE-2018-8120

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

CWE-ID: CWE-119 - Memory corruption

Description:

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

The vulnerability exists due to boundary error in win32k.sys driver. A local user can execute arbitrary code with SYSTEM privileges.

Note: this vulnerability is being actively exploited in limited targeted attacks.

Public Exploits:

- Microsoft Windows - SetImeInfoEx Win32k NULL Pointer Dereference (Metasploit) [Exploit-DB]

External links:

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8120
https://www.welivesecurity.com/2018/05/15/tale-two-zero-days/
https://blog.malwarebytes.com/threat-analysis/2018/05/adobe-reader-zero-day-discovered-alongside-windows-vulnerability/

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.