CVE-2015-1570 in FortiClient
Summary
by MITRE
The Endpoint Control protocol implementation in Fortinet FortiClient 5.2.3.091 for Android and 5.2.028 for iOS does not validate certificates, which makes it easier for man-in-the-middle attackers to spoof servers via a crafted certificate.
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Analysis
by VulDB Data Team • 04/11/2018
The vulnerability identified as CVE-2015-1570 resides within the Endpoint Control protocol implementation of Fortinet FortiClient versions 5.2.3.091 for Android and 5.2.028 for iOS. This flaw represents a critical security weakness that fundamentally undermines the integrity of the communication channel between mobile devices and enterprise servers. The issue stems from the absence of proper certificate validation mechanisms within the mobile security client, creating a pathway for malicious actors to exploit the trust relationship that should exist between legitimate endpoints and corporate infrastructure.
The technical flaw manifests as a complete failure to validate digital certificates during the authentication process, which directly violates fundamental principles of secure communication protocols. When FortiClient fails to verify certificate authenticity, it allows attackers to present forged certificates that appear legitimate to the mobile client. This vulnerability specifically enables man-in-the-middle attacks by permitting attackers to establish fraudulent connections that bypass normal security controls. The implementation lacks proper certificate chain validation, issuer verification, and cryptographic signature checks that are essential for maintaining secure communications.
The operational impact of this vulnerability extends beyond simple network interception, as it fundamentally compromises the security posture of organizations relying on FortiClient for mobile endpoint protection. Attackers can leverage this weakness to impersonate legitimate corporate servers, potentially gaining access to sensitive corporate data, intercepting encrypted communications, and executing further attacks within the network perimeter. The vulnerability affects organizations using FortiClient for mobile device management, remote access, and secure network connectivity, making it particularly dangerous in environments where mobile workers access corporate resources. This weakness essentially transforms the mobile security client from a protective barrier into a potential entry point for attackers.
Organizations should immediately implement mitigations including updating to patched versions of FortiClient where available, implementing additional network monitoring to detect anomalous certificate behavior, and deploying certificate pinning mechanisms where possible. The vulnerability aligns with CWE-295 which addresses improper certificate validation and relates to ATT&CK technique T1573.002 for securing communications protocols. Security teams should also consider implementing network segmentation and additional authentication layers to reduce the attack surface, while monitoring for unusual certificate validation failures that might indicate exploitation attempts. The incident highlights the critical importance of certificate validation in mobile security implementations and underscores the need for comprehensive security testing of mobile client applications.