CVE-2008-5736 in FreeBSD
Summary
by MITRE
Multiple unspecified vulnerabilities in FreeBSD 6 before 6.4-STABLE, 6.3 before 6.3-RELEASE-p7, 6.4 before 6.4-RELEASE-p1, 7.0 before 7.0-RELEASE-p7, 7.1 before 7.1-RC2, and 7 before 7.1-PRERELEASE allow local users to gain privileges via unknown attack vectors related to function pointers that are "not properly initialized" for (1) netgraph sockets and (2) bluetooth sockets.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability described in CVE-2008-5736 represents a critical privilege escalation issue affecting multiple versions of the FreeBSD operating system. This flaw manifests in the improper initialization of function pointers within kernel space, specifically impacting two distinct subsystems: netgraph sockets and bluetooth sockets. The vulnerability exists in FreeBSD versions prior to specific release points including 6.4-STABLE, 6.3-RELEASE-p7, 6.4-RELEASE-p1, 7.0-RELEASE-p7, 7.1-RC2, and 7.1-PRERELEASE, creating a window of exposure across several major release lines. The root cause stems from the failure to properly initialize function pointer variables during socket initialization processes, creating potential attack vectors that could be exploited by local malicious users.
The technical implementation of this vulnerability involves function pointer manipulation within kernel-level socket handling code. When netgraph sockets or bluetooth sockets are created, certain function pointers that control the behavior of these socket operations are not properly initialized to valid kernel function addresses. This initialization failure creates a scenario where these pointers may contain unpredictable values or point to arbitrary memory locations, potentially allowing attackers to redirect execution flow. The vulnerability specifically affects the kernel's socket subsystem where function pointers are used to dispatch operations to appropriate handler functions, and the improper initialization creates a condition where these pointers can be manipulated to execute arbitrary code with kernel privileges.
From an operational impact perspective, this vulnerability enables local privilege escalation attacks that can be particularly dangerous in multi-user environments or systems where untrusted users have access to the system. The attack requires local access to the target system, making it less immediately exploitable than remote vulnerabilities, but the privilege escalation potential means that attackers who can execute code locally can elevate their privileges to root level. This creates significant risk for systems where local access might be obtained through social engineering, compromised accounts, or other attack vectors that could provide a foothold for exploitation. The vulnerability affects core networking functionality and could potentially be leveraged to gain complete system control, making it a high-priority issue for system administrators.
The mitigation strategy for this vulnerability requires immediate deployment of security patches provided by FreeBSD, specifically targeting the affected release versions and ensuring proper function pointer initialization in the netgraph and bluetooth socket subsystems. System administrators should prioritize updating to the patched versions of FreeBSD, with particular attention to the specific release points mentioned in the CVE description. Additionally, implementing proper access controls and monitoring for unauthorized local access attempts can help detect potential exploitation attempts. Organizations should also consider conducting vulnerability assessments to identify systems running affected FreeBSD versions and ensure all patches are properly applied. This vulnerability aligns with CWE-457, which covers the use of uninitialized variables, and represents a classic example of how improper initialization can create security flaws in kernel code that can be exploited for privilege escalation. The attack pattern associated with this vulnerability would typically involve local execution followed by exploitation of the uninitialized function pointer to gain elevated privileges, fitting within ATT&CK framework domain of privilege escalation through kernel exploits.