FortiOS & FortiProxy SSL-VPN Flaw Allows IP Spoofing via Malicious Packets

A critical vulnerability has been discovered in Fortinet’s FortiOS SSL-VPN and FortiProxy SSL-VPN.

The flaw, identified as FG-IR-23-225, allows attackers to spoof IP addresses and bypass security controls by sending specially crafted packets. It affects multiple versions of FortiOS and FortiProxy.

According to the advisory published by Fortinet, the vulnerability stems from improper validation of packets within the SSL-VPN portal and proxy services.

An attacker can exploit this issue by crafting malicious packets that manipulate the source IP address, effectively spoofing their identity and potentially gaining unauthorized access to protected network resources.

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The affected products include FortiOS versions from 7.0.0 to 7.2.3 and FortiProxy versions from 7.0.0 to 7.2.2.

Fortinet has released patches to address the vulnerability and urges customers to upgrade to the latest fixed versions as soon as possible.

To mitigate the risk, Fortinet recommends the following steps:

• Upgrade FortiOS to versions 7.2.4 or 7.0.10 and higher
• Upgrade FortiProxy to versions 7.2.3 or 7.0.9 and higher
• If immediate upgrades are not feasible, apply the provided workarounds detailed in the advisory

The vulnerability has been assigned a CVE identifier, CVE-2023-27997, with a CVSS score of 9.3, indicating a critical severity level.

Fortinet emphasizes promptly addressing this issue to prevent potential security breaches and protect sensitive data.

As of the publication of this article, there have been no reports of the vulnerability being actively exploited in the wild.

However, with the flaw being publicly disclosed, it is crucial for organizations using affected Fortinet products to take immediate action and apply the necessary patches or workarounds.

This incident serves as a reminder of the ongoing need for robust security measures and the timely application of software updates to mitigate the risk of cyber threats.

Organizations are advised to closely monitor their Fortinet deployments, review the provided advisory, and take appropriate steps to secure their networks.

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