CVE-2015-6923 in VBox Communications Satellite Express Protocol
Summary
by MITRE
The ndvbs module in VBox Communications Satellite Express Protocol 2.3.17.3 allows local users to write to arbitrary physical memory locations and gain privileges via a 0x00000ffd ioctl call.
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Analysis
by VulDB Data Team • 06/24/2024
The vulnerability identified as CVE-2015-6923 resides within the ndvbs kernel module of VBox Communications Satellite Express Protocol version 2.3.17.3, representing a critical privilege escalation flaw that enables local attackers to manipulate physical memory directly. This issue stems from inadequate input validation and privilege checks within the ioctl handling mechanism, specifically when processing the 0x00000ffd command code. The vulnerability operates at the kernel level, where the module fails to properly validate the parameters associated with the ioctl call, creating an opportunity for malicious code execution with elevated privileges. The ndvbs module, designed to manage satellite communications hardware, exposes a direct interface to physical memory operations through this flawed ioctl implementation, bypassing normal kernel security boundaries.
The technical exploitation of this vulnerability involves a local attacker who can craft a malicious ioctl call with the specific command code 0x00000ffd, which then allows the module to write to arbitrary physical memory addresses without proper authorization. This represents a classic kernel-level memory corruption vulnerability that aligns with CWE-787, representing an out-of-bounds write condition that can lead to privilege escalation. The flaw demonstrates poor input sanitization and lacks proper access control mechanisms, enabling any local user to potentially gain root privileges by manipulating memory locations that should be protected. This vulnerability directly violates the principle of least privilege and represents a failure in kernel module security design that can be categorized under ATT&CK technique T1068, which covers privilege escalation through kernel exploits.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with direct access to physical memory, potentially enabling them to modify critical system components, inject malicious code into running processes, or manipulate kernel data structures. An attacker could leverage this capability to establish persistent backdoors, modify system binaries, or disable security mechanisms entirely. The vulnerability affects systems running the specific version of VBox Communications Satellite Express Protocol, particularly those utilizing the ndvbs kernel module for satellite communication management. Given that this is a local privilege escalation vulnerability, the attack surface is limited to systems where local access is already possible, but the potential for lateral movement and system compromise remains significant. The exploitability of this vulnerability is enhanced by the fact that it requires minimal privileges to initiate, making it particularly dangerous in environments where local user access is common or where privilege separation is not properly enforced.
Mitigation strategies for CVE-2015-6923 should focus on immediate patching of the VBox Communications Satellite Express Protocol software to a version that properly validates ioctl parameters and implements appropriate access controls. System administrators should also consider disabling the ndvbs kernel module if satellite communication functionality is not required, as this eliminates the attack surface entirely. Additional protective measures include implementing kernel module signing requirements, enabling kernel address space layout randomization, and monitoring for suspicious ioctl activity. Security teams should conduct thorough vulnerability assessments to identify systems running the affected software version and ensure that all kernel modules are properly maintained and updated according to vendor security advisories. The vulnerability highlights the importance of proper kernel module security practices and the necessity of implementing robust input validation mechanisms at all levels of system operation.