CVE-2007-4304 in CerbNG
Summary
by MITRE
CerbNG for FreeBSD 4.8 does not properly implement VM protection when attempting to prevent system call wrapper races, which allows local users to have an unknown impact related to an "incorrect write protection of pages".
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Analysis
by VulDB Data Team • 02/03/2019
The vulnerability described in CVE-2007-4304 affects CerbNG for FreeBSD 4.8, a system that implements virtual machine protection mechanisms to prevent race conditions during system call wrapper operations. This flaw represents a critical design weakness in the memory protection implementation that could potentially allow local attackers to exploit memory management inconsistencies within the operating system kernel.
The technical root cause lies in the improper handling of page write protection mechanisms during system call wrapper execution. When the system attempts to prevent race conditions between virtual machine operations and system calls, the implementation fails to correctly manage memory page permissions. This incorrect write protection of pages creates a scenario where local users can potentially manipulate memory access controls to execute unauthorized operations or gain elevated privileges.
This vulnerability operates at the kernel level within the FreeBSD 4.8 operating system environment, specifically targeting the virtual machine protection subsystem. The flaw manifests when the system attempts to prevent race conditions between different execution contexts during system call processing. The improper implementation means that page protection mechanisms that should prevent unauthorized writes to critical memory regions are not functioning as intended, creating potential attack vectors for local privilege escalation.
The operational impact of this vulnerability extends beyond simple memory protection failures. Attackers with local access could potentially exploit this weakness to manipulate kernel memory structures, bypass security controls, or execute arbitrary code with elevated privileges. The unknown impact referenced in the CVE description indicates that the specific consequences could vary depending on system configuration and execution context, making the vulnerability particularly dangerous as it could enable various types of malicious activities.
According to CWE standards, this vulnerability maps to CWE-284: Improper Access Control, specifically related to inadequate memory protection mechanisms. The ATT&CK framework would categorize this under privilege escalation techniques, particularly T1068: Exploitation for Privilege Escalation, where local users leverage kernel-level weaknesses to gain elevated system privileges. The vulnerability also aligns with T1543: Create or Modify System Process, as it could enable attackers to modify system processes through memory manipulation.
Mitigation strategies should focus on updating to newer versions of FreeBSD that address memory protection implementation flaws, implementing proper kernel memory management controls, and applying security patches that correct the page write protection mechanisms. System administrators should also consider implementing additional monitoring for suspicious memory access patterns and ensure that all system call wrappers properly validate memory protection states before executing critical operations. The fundamental fix requires correcting the virtual machine protection implementation to properly manage page write permissions during system call wrapper operations.