CVE-2015-4077 in FortiClient
Summary
by MITRE
The (1) mdare64_48.sys, (2) mdare32_48.sys, (3) mdare32_52.sys, and (4) mdare64_52.sys drivers in Fortinet FortiClient before 5.2.4 allows local users to read arbitrary kernel memory via a 0x22608C ioctl call.
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Analysis
by VulDB Data Team • 07/21/2025
The vulnerability identified as CVE-2015-4077 affects the Fortinet FortiClient security software, specifically targeting four kernel-mode drivers including mdare64_48.sys, mdare32_48.sys, mdare32_52.sys, and mdare64_52.sys. This issue represents a critical privilege escalation vector that enables local attackers to access sensitive kernel memory regions through improper input validation within the ioctl interface. The vulnerability resides in the driver's handling of the 0x22608C ioctl command, which lacks proper bounds checking and memory access controls. The affected versions of FortiClient prior to 5.2.4 fail to validate the parameters passed to these specific driver interfaces, creating an exploitable condition that could allow malicious code execution at kernel level. This flaw directly violates the principle of least privilege and demonstrates poor input validation practices that are commonly categorized under CWE-129, which addresses insufficient input validation leading to buffer overflows and memory corruption issues.
The technical exploitation of this vulnerability occurs when a local user crafts a malicious ioctl call targeting one of the affected driver interfaces with the specific command code 0x22608C. The drivers fail to properly validate the input parameters, particularly the size and content of the data structure being passed, allowing the attacker to manipulate memory access patterns and potentially read arbitrary kernel memory locations. This type of vulnerability falls under the ATT&CK technique T1055.001 for kernel injection and privilege escalation, as it enables local users to escalate their privileges from user-level to kernel-level access. The memory read operations bypass normal kernel memory protection mechanisms, allowing attackers to potentially extract sensitive information such as encryption keys, passwords, or other confidential data stored in kernel memory. The vulnerability's impact extends beyond simple information disclosure, as it provides a foundation for more sophisticated attacks including privilege escalation and system compromise.
The operational impact of CVE-2015-4077 is significant for organizations using affected FortiClient versions, as it creates a persistent backdoor for local attackers who may already have user-level access to systems. Once exploited, the vulnerability allows attackers to gain complete control over the system's kernel memory space, potentially enabling them to modify critical system components, disable security features, or extract sensitive information from memory. This vulnerability affects enterprise environments where FortiClient is deployed for endpoint protection, creating a scenario where an attacker with minimal privileges could escalate to system administrator level access. The impact is particularly severe because FortiClient is designed to provide security protection, making this a classic case of a security tool being compromised. Organizations using affected versions are vulnerable to both insider threats and attackers who gain initial access through other means, as the vulnerability does not require network connectivity or external exploitation. The vulnerability represents a fundamental flaw in the driver architecture and highlights the importance of proper kernel-mode security boundaries.
Mitigation strategies for CVE-2015-4077 primarily involve upgrading to FortiClient version 5.2.4 or later, which includes patches that address the improper ioctl parameter validation. Organizations should implement comprehensive patch management procedures to ensure all affected systems are updated promptly. Additionally, system administrators should consider implementing additional security controls such as driver signature enforcement, kernel address space layout randomization, and monitoring for suspicious ioctl activity. The vulnerability underscores the importance of secure coding practices and proper input validation in kernel-mode drivers, as outlined in industry standards such as the CERT Secure Coding Standards and NIST SP 800-155 guidelines for kernel security. Organizations should also conduct regular security assessments of their endpoint protection software and maintain updated threat intelligence to identify similar vulnerabilities in other security tools. The remediation process should include thorough testing of patches in controlled environments before widespread deployment to ensure compatibility with existing security infrastructure and prevent service disruptions.