Unauthenticated remote code execution in FortiOS and FortiProxy SSL-VPN

1) Heap-based buffer overflow

EUVDB-ID: #VU77175

Risk: Critical

CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2023-27997

CWE-ID: CWE-122 - Heap-based Buffer Overflow

Exploit availability: Yes

Description

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

The vulnerability exists due to a boundary error within the SSL-VPN feature. A remote non-authenticated attacker can send specially crafted requests to the SSL-VPN interface, trigger a heap-based buffer overflow 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.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FortiOS: 6.0.0 - 7.2.4

FortiProxy: 1.1.0 - 7.2.3

FortiOS-6K7K: 6.0.10 - 7.0.10

External links

http://fortiguard.fortinet.com/psirt/FG-IR-23-097
http://www.fortinet.com/blog/psirt-blogs/analysis-of-cve-2023-27997-and-clarifications-on-volt-typhoon-campaign

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.