CVE-2014-3711 in FreeBSD
Summary
by MITRE
namei in FreeBSD 9.1 through 10.1-RC2 allows remote attackers to cause a denial of service (memory exhaustion) via vectors that trigger a sandboxed process to look up a large number of nonexistent path names.
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Analysis
by VulDB Data Team • 02/23/2022
The vulnerability identified as CVE-2014-3711 affects FreeBSD operating systems version 9.1 through 10.1-RC2 and resides within the namei subsystem which is responsible for path name resolution. This critical flaw enables remote attackers to execute a denial of service attack by triggering memory exhaustion through the manipulation of sandboxed processes. The vulnerability specifically targets the way the system handles lookups for nonexistent path names, creating a scenario where memory resources become depleted through repeated or excessive path resolution attempts.
The technical implementation of this vulnerability occurs within the namei function which is part of the kernel's file system subsystem. When a sandboxed process attempts to resolve path names that do not exist, the system's path resolution mechanism fails to properly handle the large number of failed lookups, leading to progressive memory consumption. This flaw is particularly dangerous because it can be exploited remotely without requiring authentication, and the attack can be executed through processes that are normally restricted by sandboxing mechanisms. The vulnerability manifests as a gradual exhaustion of available memory resources, ultimately causing the system to become unresponsive or crash entirely.
From an operational impact perspective, this vulnerability poses significant risks to FreeBSD systems deployed in production environments where remote access is possible. The denial of service condition can affect system availability and potentially disrupt critical services that depend on file system operations. The attack requires minimal privileges and can be executed against systems that are otherwise protected by sandboxing, making it particularly concerning for multi-tenant environments or systems where process isolation is expected to provide security boundaries. The memory exhaustion occurs gradually, potentially allowing attackers to consume system resources over time until the system becomes unusable.
Mitigation strategies for CVE-2014-3711 involve immediate patching of affected FreeBSD systems to versions that contain the fix for the namei subsystem memory handling. System administrators should prioritize updating their FreeBSD installations to versions that have addressed this specific vulnerability. Additionally, monitoring for unusual memory consumption patterns and implementing resource limits on sandboxed processes can help detect and prevent exploitation attempts. The vulnerability aligns with CWE-400 which categorizes improper handling of resource exhaustion conditions, and represents a typical example of how kernel-level memory management flaws can be exploited to cause denial of service attacks. Organizations should also consider implementing network segmentation and access controls to limit exposure to remote exploitation vectors while awaiting patch deployment. This vulnerability demonstrates the importance of proper resource management in kernel subsystems and the potential for seemingly benign operations to be leveraged for system compromise through resource exhaustion attacks.