CVE-2008-1140 in DESlock
Summary
by MITRE
DLMFDISK.sys 1.2.0.27 in DESlock+ 3.2.6 and earlier allows local users to gain privileges via a certain DLKFDISK_IOCTL request to \\.\DLKFDisk_Control that overwrites a data structure associated with a mounted pseudo-filesystem, aka the "ring0 SYSTEM" vulnerability.
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Analysis
by VulDB Data Team • 10/17/2024
The vulnerability identified as CVE-2008-1140 represents a critical privilege escalation flaw within the DESlock+ encryption software suite, specifically affecting versions 3.2.6 and earlier. This issue resides in the DLMFDISK.sys kernel driver component with version 1.2.0.27, which handles disk management operations for the DESlock+ filesystem. The vulnerability stems from improper input validation and memory management within the kernel-mode driver that processes IOCTL (Input/Output Control) requests. When a local user executes a specially crafted DLKFDISK_IOCTL request against the device handle \.\DLKFDisk_Control, the driver fails to properly validate the input parameters, leading to a dangerous buffer overflow condition. This flaw allows an attacker to manipulate kernel memory structures associated with mounted pseudo-filesystems, effectively bypassing normal security boundaries between user and kernel modes.
The technical exploitation of this vulnerability leverages the fundamental principle of kernel-mode privilege escalation through improper kernel driver implementation. The DLMFDISK.sys driver operates at ring0 privilege level, which is the highest privilege level in x86 architecture, where all system resources are accessible and no protection mechanisms are enforced. The vulnerability manifests when the driver receives an IOCTL request that overwrites data structures within kernel memory, specifically those associated with filesystem mounting operations. This memory corruption can be exploited to execute arbitrary code with SYSTEM-level privileges, effectively granting full control over the compromised system. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which addresses out-of-bounds writes in heap-based buffers, both of which are common in kernel-mode drivers where memory management is critical. The attack vector requires local system access, making it particularly dangerous as it can be exploited by any user with access to the system, regardless of their initial privilege level.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security model of the DESlock+ encryption system. When successfully exploited, the vulnerability allows attackers to bypass the encryption protection mechanisms that DESlock+ is designed to provide, potentially exposing sensitive data to unauthorized access. The vulnerability affects the integrity and confidentiality of encrypted data stored on systems running vulnerable versions of DESlock+, as an attacker with SYSTEM privileges can directly access the underlying filesystem without proper authentication. This compromise undermines the core security assumptions of the encryption solution and can lead to complete system takeover. From an enterprise security perspective, this vulnerability represents a significant risk as it allows lateral movement and persistence within networks where DESlock+ is deployed. The vulnerability also demonstrates poor security practices in kernel driver development, as proper input validation, bounds checking, and memory management should have prevented such an exploitable condition.
Mitigation strategies for CVE-2008-1140 should focus on immediate remediation through vendor-supplied patches and updates to DESlock+ versions that address the kernel driver vulnerability. Organizations should implement strict access controls and privilege separation to limit local user access where possible, as the vulnerability requires local system access for exploitation. System administrators should conduct thorough vulnerability assessments to identify all systems running vulnerable versions of DESlock+ and prioritize patch deployment. The remediation approach should also include monitoring for suspicious IOCTL activity and kernel-mode memory access patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing kernel-mode exploit detection mechanisms and maintaining up-to-date system monitoring solutions that can detect anomalous behavior indicative of privilege escalation attacks. This vulnerability highlights the critical importance of proper kernel-mode security practices and demonstrates the potential consequences of inadequate input validation in security-critical system components. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting kernel-mode exploitation methods that leverage driver vulnerabilities to gain SYSTEM-level access. Organizations should also consider implementing additional security controls such as application whitelisting and mandatory access controls to reduce the overall attack surface and limit the potential impact of such vulnerabilities in their environments.