CVE-2011-4062 in FreeBSD
Summary
by MITRE
Buffer overflow in the kernel in FreeBSD 7.3 through 9.0-RC1 allows local users to cause a denial of service (panic) or possibly gain privileges via a bind system call with a long pathname for a UNIX socket.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 08/07/2024
The vulnerability identified as CVE-2011-4062 represents a critical buffer overflow flaw within the FreeBSD kernel affecting versions 7.3 through 9.0-RC1. This issue manifests specifically during the execution of the bind system call when processing UNIX socket paths that exceed predetermined length limits. The flaw resides in the kernel's handling of socket pathname validation and buffer management, creating a condition where insufficient bounds checking allows malicious input to overwrite adjacent memory regions. Such buffer overflow conditions are classified under CWE-121 as classic stack-based buffer overflow vulnerabilities that can lead to arbitrary code execution or system instability.
The technical implementation of this vulnerability exploits the kernel's insufficient validation of pathname lengths during UNIX socket binding operations. When a local user submits a bind system call with an excessively long pathname, the kernel fails to properly enforce length constraints before copying the pathname into internal buffers. This oversight creates a scenario where the buffer overflow can trigger kernel panic conditions or potentially enable privilege escalation attacks. The vulnerability specifically impacts the kernel's socket subsystem where it processes UNIX domain socket paths, making it particularly dangerous for systems utilizing Unix sockets for inter-process communication. The attack vector requires local user access but can result in either system denial of service or privilege elevation depending on exploitation success.
Operationally, this vulnerability poses significant risks to FreeBSD systems as it allows local attackers to either crash the system through kernel panics or potentially escalate privileges to gain root access. The denial of service aspect can be particularly damaging in server environments where system availability is critical, while the privilege escalation component presents a more severe threat to system integrity. The impact extends beyond individual system compromise to potentially affect entire network infrastructure relying on FreeBSD systems for critical services. Attackers can leverage this vulnerability through local shell access or by exploiting other initial access vectors that lead to local execution capabilities on the target system. The vulnerability's presence in multiple FreeBSD versions from 7.3 through 9.0-RC1 indicates a prolonged exposure window that increases the likelihood of exploitation in production environments.
Mitigation strategies for CVE-2011-4062 focus primarily on immediate system updates and patch management to address the underlying kernel vulnerability. Organizations should prioritize upgrading to FreeBSD versions that contain the relevant security patches, specifically those beyond 9.0-RC1 where the vulnerability has been resolved. System administrators should implement monitoring for unusual bind system call patterns and pathname lengths that may indicate exploitation attempts. Additional protective measures include restricting local user access where possible, implementing proper system hardening practices, and deploying intrusion detection systems that can identify anomalous behavior patterns associated with buffer overflow exploitation attempts. The vulnerability aligns with ATT&CK technique T1068 which covers local privilege escalation through kernel vulnerabilities, making it a target for both casual attackers seeking system disruption and more sophisticated threat actors aiming for persistent access. Regular security audits and kernel security assessments should be conducted to identify similar vulnerabilities in system components that may present analogous buffer management flaws.