CVE-2007-5761 in netOctopus
Summary
by MITRE
The NantSys device 5.0.0.115 in Motorola netOctopus 5.1.2 build 1011 has weak permissions for the \\.\NantSys device interface (nantsys.sys), which allows local users to gain privileges or cause a denial of service (system crash), as demonstrated by modifying the SYSENTER_EIP_MSR CPU Model Specific Register (MSR) value.
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Analysis
by VulDB Data Team • 08/03/2019
The vulnerability identified as CVE-2007-5761 affects the Motorola netOctopus 5.1.2 system with NantSys device version 5.0.0.115, representing a critical privilege escalation and system stability issue within the device driver interface. This flaw resides in the \.\NantSys device interface located at nantsys.sys, which demonstrates inadequate access control mechanisms that permit local users to manipulate system-critical components without proper authorization. The vulnerability stems from weak permissions assigned to the device driver interface, creating an attack surface that can be exploited by malicious local actors to gain elevated privileges or disrupt system operations entirely.
The technical exploitation of this vulnerability involves direct manipulation of the SYSENTER_EIP_MSR CPU Model Specific Register, which serves as a critical component in the Windows kernel's system call handling mechanism. By modifying this specific MSR value, an attacker can potentially redirect execution flow within the kernel space, leading to privilege escalation from standard user level to kernel level access. This type of exploitation directly violates the fundamental security principles of privilege separation and kernel protection, as it allows unauthorized code execution in the most privileged system context. The SYSENTER_EIP_MSR register specifically controls the entry point for system calls, making its manipulation particularly dangerous for achieving persistent elevated access.
The operational impact of this vulnerability extends beyond simple privilege escalation to include potential system instability and complete system crashes. When local users can modify critical CPU registers like SYSENTER_EIP_MSR, they gain the ability to cause denial of service conditions that can result in system crashes or reboots. This creates an environment where malicious actors can either gain unauthorized administrative access or disrupt legitimate system operations, depending on their objectives. The vulnerability affects the entire system stability since the MSR modification can corrupt the kernel's execution flow, potentially leading to unpredictable behavior or complete system failure.
From a cybersecurity perspective, this vulnerability aligns with CWE-276, which addresses improper permissions for critical resources, and represents a classic example of insufficient access control in kernel-mode drivers. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the use of kernel exploits to gain SYSTEM-level access. The weakness in the device driver interface demonstrates poor security implementation practices that violate the principle of least privilege, where system resources should only be accessible to authorized entities with appropriate security contexts. Organizations should consider this vulnerability as part of their broader vulnerability management strategy, particularly when assessing legacy systems that may still be operational.
Mitigation strategies for CVE-2007-5761 require immediate attention through patch management procedures and system hardening measures. The primary recommendation involves applying vendor-supplied patches or firmware updates that address the weak permissions in the nantsys.sys driver interface. System administrators should also implement additional access controls through Windows security policies, ensuring that only authorized users can interact with the specific device interface. Regular security audits of device drivers and kernel interfaces should be conducted to identify similar permission weaknesses. Network segmentation and monitoring solutions can help detect unauthorized access attempts to critical system resources, while maintaining detailed logging of driver access events to support incident response activities. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing robust access control mechanisms in all system components, particularly those with kernel-level access privileges.