Zero-day vulnerability in Microsoft Internet Explorer

Double Free
CVE-2021-26411

The vulnerability was used by the Lazarus group to target security researchers worldwide.

Vulnerability details

Advisory: SB2021020701 - Remote code execution in Microsoft Internet Explorer

Vulnerable component: Microsoft Internet Explorer

CVE-ID: CVE-2021-26411

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

CWE-ID: CWE-415 - Double Free

Description:

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing ".mht" files. A remote attacker can trick the victim to visit a specially crafted webpage, trigger a double free error and execute arbitrary code on the target system.

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

Note, the vulnerability is being actively exploited in the wild.

External links:

https://enki.co.kr/blog/2021/02/04/ie_0day.html

https://twitter.com/dnpushme/status/1357264755333816320


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.