CVE-2023-29175 in FortiOS
Summary
by MITRE • 06/13/2023
An improper certificate validation vulnerability [CWE-295] in FortiOS 6.2 all versions, 6.4 all versions, 7.0.0 through 7.0.10, 7.2.0 and FortiProxy 1.2 all versions, 2.0 all versions, 7.0.0 through 7.0.9, 7.2.0 through 7.2.3 may allow a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the communication channel between the vulnerable device and the remote FortiGuard's map server.
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Analysis
by VulDB Data Team • 06/13/2023
The vulnerability identified as CVE-2023-29175 represents a critical certificate validation flaw classified under CWE-295, which specifically addresses improper certificate validation mechanisms. This weakness affects multiple versions of Fortinet's FortiOS and FortiProxy products, creating a significant security risk for organizations relying on these network security devices. The vulnerability stems from insufficient validation of SSL/TLS certificates when establishing connections with FortiGuard's map server, which serves as a critical component for threat intelligence and security updates. The flaw exists across FortiOS versions 6.2, 6.4, 7.0.0 through 7.0.10, 7.2.0, and FortiProxy versions 1.2, 2.0, 7.0.0 through 7.0.9, 7.2.0 through 7.2.3, indicating a widespread impact across Fortinet's product ecosystem.
The technical implementation of this vulnerability allows remote and unauthenticated attackers to exploit the weak certificate validation process during communication with FortiGuard's map server. When devices attempt to establish secure connections for threat intelligence updates or security data synchronization, the flawed validation mechanism fails to properly verify the authenticity and integrity of the server certificates. This weakness enables attackers to perform man-in-the-middle attacks by intercepting and modifying communication between vulnerable devices and FortiGuard's infrastructure. The attack vector requires no authentication credentials from the attacker, making it particularly dangerous as it can be exploited from anywhere on the network. The vulnerability specifically targets the certificate validation logic within the SSL/TLS handshake process, where the system should verify certificate chains, expiration dates, and issuer authenticity but fails to perform these critical checks properly.
The operational impact of this vulnerability extends beyond simple network interception, as it compromises the integrity of security updates and threat intelligence that organizations rely upon for their defensive posture. When devices fail to validate certificates properly, they become susceptible to receiving malicious updates or being redirected to compromised servers that could distribute malware or provide false security information. This creates a cascading effect where organizations may unknowingly deploy compromised security configurations or receive incorrect threat intelligence that could lead to further exploitation. The vulnerability undermines the fundamental security model of Fortinet's products, as it allows attackers to manipulate the trust relationships that are essential for maintaining secure communications. Network administrators may experience false security alerts or fail to receive legitimate security updates, while the actual threat landscape becomes distorted through the manipulation of communication channels.
Organizations affected by CVE-2023-29175 should implement immediate mitigations including updating to patched versions of FortiOS and FortiProxy software, which Fortinet has released to address this specific validation weakness. The vulnerability aligns with ATT&CK technique T1566.002 for credential access through phishing and T1041 for data encryption for impact, as it enables attackers to manipulate security communications and potentially gain unauthorized access to network resources. Security teams should also consider implementing network monitoring to detect unusual communication patterns with FortiGuard servers and establish alternative verification mechanisms for security updates. Additionally, organizations should review their certificate management policies and consider implementing additional validation layers beyond the default certificate checking mechanisms provided by these devices. The remediation process must include thorough testing of patched firmware to ensure that the certificate validation improvements do not introduce compatibility issues with existing network configurations while maintaining the security posture against this specific man-in-the-middle attack vector.