Fortinet FortiOS sslvpnd Remote Code Execution Vulnerability (CVE-2022-42475)

Overview

Recently, NSFOCUS CERT detected that Fortinet officially fixed a remote code execution vulnerability (CVE-2022-42475) in FortiOS sslvpnd. Due to the flaw in sslvpnd’s validation of user input, an unauthenticated attacker can trigger a buffer overflow by sending a specially crafted packet, which can eventually execute arbitrary code on the target system. The CVSS score is 9.8, and it has been detected to be exploited in the wild. Relevant users are requested to take protective measures as soon as possible.

Fortinet FortiOS is Fortinet’s security operating system dedicated to the FortiGate network security platform. The system provides users with various security functions such as firewall, anti-virus, IPSec/SSLVPN, Web content filtering and anti-spam.

Reference link:

https://fortiguard.fortinet.com/psirt/FG-IR-22-398

Scope of Impact

Affected version

• 7.2.0 <= FortiOS <= 7.2.2
• 7.0.0 <= FortiOS <= 7.0.8
• 6.4.0 <= FortiOS <= 6.4.10
• 6.2.0 <= FortiOS <= 6.2.11
• 7.0.0 <= FortiOS-6K7K <= 7.0.7
• 6.4.0 <= FortiOS-6K7K <= 6.4.9
• 6.2.0 <= FortiOS-6K7K <= 6.2.11
• 6.0.0 <= FortiOS-6K7K <= 6.0.14

Unaffected version

• FortiOS >= 7.2.3
• FortiOS >= 7.0.9
• FortiOS >= 6.4.11
• FortiOS >= 6.2.12
• FortiOS-6K7K >= 7.0.8
• FortiOS-6K7K >= 6.4.10
• FortiOS-6K7K >= 6.2.12
• FortiOS-6K7K >= 6.0.15

Vulnerability Detection

Users can conduct self-examination according to the officially announced IOC to verify whether their system has been attacked.

1. Check the system for the following log entries:

Logdesc=”Application crashed” and msg=”[…] application:sslvpnd,[…], Signal 11 received, Backtrace: […]”

2. Check whether the following files exist in the system:

Users can check the above files with the following command:

3. Check FortiGate for connections to the following suspicious IP addresses:

Mitigation

At present, the official security version has been released to fix this vulnerability. It is recommended that affected users upgrade their protection in time: https://docs.fortinet.com/product/fortigate/7.2

Statement

This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.

About NSFOCUS

NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks. The company’s Intelligent Hybrid Security strategy utilizes both cloud and on-premises security platforms, built on a foundation of real-time global threat intelligence, to provide multi-layered, unified and dynamic protection against advanced cyber attacks.

NSFOCUS works with Fortune Global 500 companies, including four of the world’s five largest financial institutions, organizations in insurance, retail, healthcare, critical infrastructure industries as well as government agencies. NSFOCUS has technology and channel partners in more than 60 countries, is a member of both the Microsoft Active Protections Program (MAPP), and the Cloud Security Alliance (CSA).

A wholly owned subsidiary of NSFOCUS Technologies Group Co., Ltd., the company has operations in the Americas, Europe, the Middle East and Asia Pacific.