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Executive Summary
On November 12, 2024, a critical vulnerability was identified in FortiOS, designated as FG-IR-23-475. This vulnerability is classified as a session fixation vulnerability (CWE-384) that could allow unauthenticated attackers to hijack user sessions through phishing SAML authentication links. The implications of this vulnerability are significant, as it may lead to unauthorized access and potential exploitation of sensitive data. Organizations utilizing affected versions of FortiOS must take immediate action to mitigate risks associated with this vulnerability.
Technical Information
The vulnerability FG-IR-23-475 is cataloged under CVE-2023-50176 and has been assigned a CVSSv3 Score of 7.1, indicating a high severity level. The vulnerability arises from improper session management, specifically related to the handling of SAML authentication links. Attackers can exploit this flaw by crafting malicious links that, when clicked by a user, can lead to session hijacking. This exploitation can result in unauthorized code execution or command execution on the affected systems, posing a severe risk to organizational security.
The affected versions of FortiOS include FortiOS 7.4 (versions 7.4.0 through 7.4.3), FortiOS 7.2 (versions 7.2.0 through 7.2.7), and FortiOS 7.0 (versions 7.0.0 through 7.0.13). Users are strongly advised to upgrade to the latest versions to mitigate the risks associated with this vulnerability. The recommended upgrade paths are to FortiOS 7.4.4 or above, FortiOS 7.2.8 or above, and FortiOS 7.0.14 or above. For detailed upgrade instructions, users can refer to the upgrade tool available at https://docs.fortinet.com/upgrade-tool.
Exploitation in the Wild
Exploitation of CVE-2023-50176 has been observed in the wild, with attackers leveraging phishing techniques to distribute malicious SAML authentication links. These links are designed to trick users into clicking them, thereby initiating a session fixation attack. Once the attacker successfully hijacks a session, they can gain unauthorized access to sensitive information and potentially execute arbitrary commands on the compromised system.
Indicators of Compromise (IOCs) associated with this vulnerability include unusual login attempts from unfamiliar IP addresses, unexpected changes in user session states, and the presence of suspicious SAML authentication requests in server logs. Organizations should monitor their systems for these IOCs to detect potential exploitation attempts.
APT Groups using this vulnerability
While specific Advanced Persistent Threat (APT) groups have not been publicly linked to the exploitation of CVE-2023-50176, the nature of the vulnerability makes it a potential target for various threat actors. APT groups often focus on sectors such as finance, healthcare, and government, where the impact of a successful attack can be particularly damaging. Organizations in these sectors should remain vigilant and implement robust security measures to protect against potential exploitation.
Affected Product Versions
The following versions of FortiOS are affected by the vulnerability FG-IR-23-475:
FortiOS 7.4: Versions 7.4.0 through 7.4.3 are affected. Users must upgrade to version 7.4.4 or above.
FortiOS 7.2: Versions 7.2.0 through 7.2.7 are affected. Users should upgrade to version 7.2.8 or above.
FortiOS 7.0: Versions 7.0.0 through 7.0.13 are affected. Users must upgrade to version 7.0.14 or above.
For further details on the affected versions and upgrade paths, please refer to the Fortinet Security Advisory at https://www.fortiguard.com/psirt/FG-IR-23-475.
Workaround and Mitigation
To mitigate the risks associated with CVE-2023-50176, organizations should implement the following strategies:
- Upgrade to the latest versions of FortiOS as specified in the affected product versions section.
- Educate users about the risks of phishing attacks and the importance of verifying the authenticity of SAML authentication links before clicking.
- Implement multi-factor authentication (MFA) to add an additional layer of security to user sessions.
- Regularly monitor logs for unusual activity and potential indicators of compromise related to session management.
By taking these proactive measures, organizations can significantly reduce their exposure to this vulnerability and enhance their overall security posture.
References
Fortinet Security Advisory: https://www.fortiguard.com/psirt/FG-IR-23-475
CISA Known Exploited Vulnerabilities Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
NVD Entry for CVE-2023-50176: https://nvd.nist.gov/vuln/detail/CVE-2023-50176
Rescana is here for you
At Rescana, we are committed to helping our customers navigate the complexities of cybersecurity. Our Continuous Threat and Exposure Management (CTEM) platform provides organizations with the tools and insights needed to identify, assess, and mitigate vulnerabilities effectively. We encourage our customers to reach out with any questions regarding this report or any other cybersecurity concerns at ops@rescana.com.