Fortinet FortiOS/FortiProxy Proxy Mode buffer underflow

Summaryinfo

A vulnerability marked as very critical has been reported in Fortinet FortiOS and FortiProxy. This affects an unknown part of the component Proxy Mode. The manipulation leads to buffer underflow. This vulnerability is documented as CVE-2023-33308. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Fortinet FortiOS and FortiProxy (Firewall Software) (the affected version is unknown). This issue affects an unknown code of the component Proxy Mode. The manipulation with an unknown input leads to a buffer underflow vulnerability. Using CWE to declare the problem leads to CWE-124. The product writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer. Impacted is confidentiality, integrity, and availability.

The weakness was released 07/11/2023 by Watchtowr as FG-IR-23-183 as confirmed advisory (Website). The advisory is shared at fortiguard.com. The identification of this vulnerability is CVE-2023-33308 since 05/22/2023. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/13/2023). The advisory points out:

A stack-based overflow vulnerability [CWE-124] in FortiOS & FortiProxy may allow a remote attacker to execute arbitrary code or command via crafted packets reaching proxy policies or firewall policies with proxy mode alongside SSL deep packet inspection.

We expect the 0-day to have been worth approximately $25k-$100k.

Upgrading eliminates this vulnerability. It is possible to mitigate the problem by applying the configuration setting Disable HTTP2. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Firewall Software

Vendor

• Fortinet

Name

• FortiOS
• FortiProxy

License

• commercial

Website

• Vendor: https://www.fortinet.com/

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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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