Remote code execution in Microsoft Word

1) Out-of-bounds write

EUVDB-ID: #VU74937

Risk: High

CVSSv3.1: 7.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2023-28311

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing untrusted input in Microsoft Office Word. A remote attacker can create a specially crafted DOCX file, trick the victim into opening it using the affected software, trigger an out-of-bounds write and execute arbitrary code on the target system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Office for Mac: 16.33 20011301 - 2019

Microsoft 365 Apps for Enterprise: 32-bit Systems - 64-bit Systems

Microsoft Word: before 16.0.10397.20021, 16.0.16227.20280

CPE2.3

• cpe:2.3:a:microsoft:office_mac:16.33:20011301:*:*:*:*:*:*
• cpe:2.3:a:microsoft:office_mac:16.34:20020900:*:*:*:*:*:*
• cpe:2.3:a:microsoft:office_mac:16.35:20030802:*:*:*:*:*:*
• cpe:2.3:a:microsoft:microsoft_365_apps_for_enterprise:32-bit Systems:*:*:*:*:*:*:*
• cpe:2.3:a:microsoft:microsoft_365_apps_for_enterprise:64-bit Systems:*:*:*:*:*:*:*
• cpe:2.3:a:microsoft:microsoft_word:*:*:*:*:*:microsoft_office:*:*

External links

http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-28311
http://www.zerodayinitiative.com/advisories/ZDI-23-384/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website or open a file.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.