CVE-2018-7249 in Windows
Summary
by MITRE
An issue was discovered in secdrv.sys as shipped in Microsoft Windows Vista, Windows 7, Windows 8, and Windows 8.1 before KB3086255, and as shipped in Macrovision SafeDisc. Two carefully timed calls to IOCTL 0xCA002813 can cause a race condition that leads to a use-after-free. When exploited, an unprivileged attacker can run arbitrary code in the kernel.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/08/2020
The vulnerability identified as CVE-2018-7249 represents a critical security flaw within the Windows kernel driver secdrv.sys which was present in multiple Windows operating systems including Vista, Windows 7, Windows 8, and Windows 8.1 prior to the installation of security update KB3086255. This driver is also distributed by Macrovision SafeDisc, indicating the vulnerability extends beyond Microsoft's own software ecosystem. The flaw manifests through a race condition that occurs when two specific IOCTL calls are executed in rapid succession, specifically targeting IOCTL code 0xCA002813. This particular vulnerability falls under CWE-362, which categorizes it as a race condition vulnerability where the timing of operations creates exploitable conditions.
The technical implementation of this vulnerability exploits a use-after-free condition that arises from improper synchronization between concurrent operations within the kernel driver. When an attacker successfully schedules two calls to the same IOCTL code with precise timing, the driver's internal memory management becomes compromised. The race condition occurs during the processing of these IOCTL operations, where memory allocated to a data structure is freed while another operation is still accessing it, creating a scenario where freed memory can be reallocated and accessed by malicious code. This fundamental flaw in driver design allows an unprivileged user account to escalate privileges and execute arbitrary code with kernel-level privileges, effectively bypassing standard user-mode security boundaries.
The operational impact of CVE-2018-7249 is severe as it enables a local privilege escalation attack that can be exploited by any user with access to the system, regardless of their initial privileges. The vulnerability does not require special permissions or elevated access to initiate the attack, making it particularly dangerous in environments where user accounts may be compromised through social engineering or other attack vectors. Once exploited, the attacker gains complete control over the system's kernel, enabling them to manipulate system memory, disable security features, install rootkits, and potentially access sensitive data. This vulnerability aligns with ATT&CK technique T1068, which describes the use of local privilege escalation techniques to gain system-level access.
The exploitation of this vulnerability demonstrates a classic example of how driver-level flaws can create pathways for complete system compromise. The use of IOCTL 0xCA002813 as the attack vector highlights the dangerous nature of Windows driver interfaces that lack proper input validation and synchronization mechanisms. Security researchers have classified this vulnerability as particularly concerning because it can be triggered through legitimate system calls that are part of normal operating procedures, making detection difficult. The fix implemented in KB3086255 addresses the root cause by introducing proper synchronization mechanisms and memory management controls within the secdrv.sys driver. Organizations should prioritize immediate deployment of this security update, as the vulnerability has been actively exploited in the wild, and the window of opportunity for attackers to leverage this flaw remains open. The vulnerability also underscores the importance of proper driver security testing and code review processes, particularly for third-party drivers like those distributed by Macrovision SafeDisc, which may not undergo the same rigorous security validation as Microsoft's own kernel components.