CVE-2011-2898 in Linux
Summary
by MITRE
net/packet/af_packet.c in the Linux kernel before 2.6.39.3 does not properly restrict user-space access to certain packet data structures associated with VLAN Tag Control Information, which allows local users to obtain potentially sensitive information via a crafted application.
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Analysis
by VulDB Data Team • 12/02/2021
The vulnerability described in CVE-2011-2898 resides within the Linux kernel's packet socket implementation, specifically in the net/packet/af_packet.c file. This issue affects kernel versions prior to 2.6.39.3 and represents a significant information disclosure flaw that impacts the security of network packet handling mechanisms. The vulnerability is particularly concerning because it allows local users to access sensitive data that should normally be restricted to kernel space operations, creating potential attack vectors for privilege escalation and information gathering.
The technical flaw stems from improper restrictions on user-space access to packet data structures that contain VLAN Tag Control Information. When applications create packet sockets using the AF_PACKET address family, they can potentially access internal kernel data structures that contain sensitive metadata about network packets. The vulnerability occurs because the kernel fails to properly validate or restrict access to these data structures, allowing user-space processes to read memory locations that contain VLAN tag information and other potentially sensitive packet metadata. This improper access control mechanism violates fundamental security principles of kernel space protection and memory isolation.
The operational impact of this vulnerability is substantial for systems running affected kernel versions, as it enables local users to extract potentially sensitive information from network packet structures. An attacker with local access could craft malicious applications that exploit this weakness to read VLAN tag control information and other packet metadata that might contain network topology details, traffic patterns, or other confidential information. This information disclosure could be leveraged to gain insights into network infrastructure, potentially aiding in more sophisticated attacks such as network reconnaissance or traffic analysis. The vulnerability specifically affects systems using packet sockets and VLAN-tagged network traffic, making it particularly relevant in enterprise environments with complex network architectures.
Mitigation strategies for CVE-2011-2898 primarily involve upgrading to kernel versions 2.6.39.3 or later, where the vulnerability has been addressed through proper access control mechanisms. System administrators should implement regular kernel updates and maintain current security patches to prevent exploitation of this and similar vulnerabilities. Additionally, monitoring network packet socket usage and implementing proper access controls for applications that require packet capture capabilities can help reduce the attack surface. The vulnerability aligns with CWE-284, which addresses improper access control in software systems, and could potentially be leveraged by attackers following techniques described in the ATT&CK framework under privilege escalation and information gathering tactics. Organizations should also consider implementing network segmentation and monitoring to detect anomalous packet socket activity that might indicate exploitation attempts.