#VU84443 Interpretation Conflict in IPSEngine - CVE-2023-40718

Vulnerability identifier: #VU84443

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-40718

CWE-ID: CWE-436

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
IPSEngine
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Fortinet, Inc

Description

The vulnerability allows a remote attacker to bypass implemented security policies.

The vulnerability exists due to an interpretation conflict when handling custom TCP flags. A remote attacker can send specially crafted TCP packets to evade NGFW policies or IPS Engine protection.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

IPSEngine: before 6.0159

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External links
https://fortiguard.com/psirt/FG-IR-23-090

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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?

No. We are not aware of malware exploiting this vulnerability.