Zero-day vulnerability in Windows

Use-after-free
CVE-2018-8453

According to Kaspersky Lab, the vulnerability is being actively exploited by the FruityArmor APT actor.

Known malware:

HEUR:Exploit.Win32.Generic
HEUR:Trojan.Win32.Generic
PDM:Exploit.Win32.Generic

Vulnerability details

Advisory: SB2018100920 - Privilege escalation in Microsoft Windows Win32k

Vulnerable component: Windows

CVE-ID: CVE-2018-8453

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-416 - Use After Free

Description:

The vulnerability allows a local attacker to gain elevated privileges on the target system.

The vulnerability exists due to a use-after free error in win32kfull!xxxDestroyWindow Win32k component. A local user can run a specially crafted application, trigger memory corruption and execute arbitrary code in kernel mode.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Note: the vulnerability has been actively exploited in the wild.

Public Exploits:

- Windows - NtUserSetWindowFNID Win32k User Callback Privilege Escalation (Metasploit) [Exploit-DB]

External links:

https://threatpost.com/microsoft-patches-zero-day-under-active-attack-by-apt/138164/
https://securelist.com/cve-2018-8453-used-in-targeted-attacks/88151/

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.