Rapid Reset attack in FortiOS and FortiProxy

1) Resource exhaustion

EUVDB-ID: #VU81728

Risk: High

CVSSv4.0: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:A/U:Amber]

CVE-ID: CVE-2023-44487

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improperly control of consumption for internal resources when handling HTTP/2 requests with compressed HEADERS frames. A remote attacker can send a sequence of compressed HEADERS frames followed by RST_STREAM frames and perform a denial of service (DoS) attack, a.k.a. "Rapid Reset".

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

Mitigation

Install update from vendor's website.

Vulnerable software versions

FortiProxy: 7.0.0 - 7.4.1

FortiOS: 7.0.0 - 7.4.2

CPE2.3

• cpe:2.3:h:fortinet:fortiproxy:7.0.14:*:*:*:*:*:*:*
• cpe:2.3:h:fortinet:fortiproxy:7.2.7:*:*:*:*:*:*:*
• cpe:2.3:h:fortinet:fortiproxy:7.4.1:*:*:*:*:*:*:*
• cpe:2.3:o:fortinet:fortios:7.0.13:*:*:*:*:*:*:*
• cpe:2.3:o:fortinet:fortios:7.2.6:*:*:*:*:*:*:*
• cpe:2.3:o:fortinet:fortios:7.4.2:*:*:*:*:*:*:*

External links

https://www.fortiguard.com/psirt/FG-IR-23-397

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 send a specially crafted request to the affected device in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.