#VU86278 Out-of-bounds write in FortiOS - CVE-2024-21762

Vulnerability identifier: #VU86278

Vulnerability risk: Critical

CVSSv4.0: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red]

CVE-ID: CVE-2024-21762

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
FortiOS
Operating systems & Components / Operating system

Vendor: Fortinet, Inc

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing HTTP requests in sslvpnd. A remote attacker can send specially crafted HTTP requests to the SSL-VPN service, trigger an out-of-bounds write and execute arbitrary code on the target system.

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

Mitigation

Install updates from vendor's website.

As a workaround it is possible to disable SSL VPN. Note, disabling just the webmode is NOT a valid workaround.

Vulnerable software versions

FortiOS: 6.0.0 - 6.0.17, 6.2.0 - 6.2.15, 6.4.0 - 6.4.14, 7.0.0 - 7.0.13, 7.2.0 - 7.2.6, 7.4.0 - 7.4.2

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External links
https://www.fortiguard.com/psirt/FG-IR-24-015

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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?

Yes. This vulnerability is being exploited in the wild.