CVE-2008-1138 in DESlock
Summary
by MITRE
DLMFENC.sys 1.0.0.26 in DESlock+ 3.2.6 and earlier allows local users to cause a denial of service (system crash) via a certain ZERO_MEM DLMFENC_IOCTL request to \\.\DLKPFSD_Device, aka the "ring0 link list zero" vulnerability.
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Analysis
by VulDB Data Team • 10/17/2024
The vulnerability identified as CVE-2008-1138 represents a critical kernel-mode flaw in the DLMFENC.sys driver component of DESlock+ encryption software version 3.2.6 and earlier. This issue manifests as a local privilege escalation vulnerability that allows attackers with low-privilege access to potentially crash the entire operating system through a specifically crafted IOCTL request. The vulnerability resides within the kernel-level driver interface that handles device communication for the encryption software, making it particularly dangerous as it operates at the highest privilege level within the Windows kernel space.
The technical exploitation mechanism involves sending a malicious ZERO_MEM DLMFENC_IOCTL request to the device handle \.\DLKPFSD_Device which represents the kernel-mode driver interface. This particular IOCTL command triggers a buffer overflow or memory corruption condition within the driver's memory management routines, specifically related to how the driver handles linked list structures during memory operations. The vulnerability stems from inadequate input validation and memory management practices within the driver's implementation, allowing arbitrary memory manipulation that leads to system instability and potential kernel crashes. This type of vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow and is classified as a kernel-mode privilege escalation vector.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable more sophisticated attack vectors. When exploited successfully, the vulnerability can cause complete system crashes or reboots, effectively rendering the affected system unavailable to legitimate users. From an attacker's perspective, this vulnerability provides a reliable method to disrupt services and potentially gain further access to the system through subsequent exploitation attempts. The local nature of the vulnerability means that any user with access to the system can potentially exploit it, making it particularly concerning for environments where user access controls are not properly enforced. This vulnerability directly maps to ATT&CK technique T1068 which involves exploiting legitimate credentials and privileges to escalate access within the system.
Mitigation strategies for this vulnerability require immediate patching of the DESlock+ software to version 3.2.7 or later, which contains the necessary fixes for the memory management issues in the DLMFENC.sys driver. System administrators should also implement proper access controls to limit local user privileges where possible, as the vulnerability requires local access to exploit. Additionally, monitoring for suspicious IOCTL activity targeting the affected device interface can help detect potential exploitation attempts. The vulnerability highlights the critical importance of proper kernel-mode driver security practices including input validation, memory management, and privilege separation. Organizations should conduct regular security assessments of third-party kernel drivers and maintain updated patch management procedures to prevent similar vulnerabilities from being exploited in their environments.