CVE-2011-2482 in Linux
Summary
by MITRE
A certain Red Hat patch to the sctp_sock_migrate function in net/sctp/socket.c in the Linux kernel before 2.6.21, as used in Red Hat Enterprise Linux (RHEL) 5, allows remote attackers to cause a denial of service (NULL pointer dereference and OOPS) via a crafted SCTP packet.
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Analysis
by VulDB Data Team • 01/03/2022
The vulnerability identified as CVE-2011-2482 represents a critical null pointer dereference flaw within the Linux kernel's SCTP (Stream Control Transmission Protocol) implementation. This issue specifically affects the sctp_sock_migrate function located in the net/sctp/socket.c file of kernel versions prior to 2.6.21. The vulnerability was particularly significant as it impacted Red Hat Enterprise Linux 5 systems that had not applied the necessary security patches, creating a widespread exposure across enterprise environments that relied on SCTP for network communication. The flaw demonstrates a classic buffer over-read condition that can be exploited through crafted SCTP packets, making it a prime target for denial of service attacks that can disrupt critical network services.
The technical exploitation of this vulnerability occurs when an attacker sends a specially crafted SCTP packet that triggers the sctp_sock_migrate function to attempt to dereference a NULL pointer. This function is responsible for migrating socket connections between different network interfaces or addresses, and the improper handling of socket structure pointers during this migration process results in a kernel panic. The kernel's response to this condition manifests as an OOPS message, which is the Linux kernel's way of reporting a fatal error, ultimately leading to a system crash or complete denial of service for the affected system. This type of vulnerability falls under CWE-476, which specifically addresses null pointer dereference conditions in software systems, making it a well-documented and dangerous class of flaw in kernel space programming.
The operational impact of CVE-2011-2482 extends far beyond simple service disruption, as it can effectively render entire network services unavailable to legitimate users. In enterprise environments where SCTP is used for mission-critical applications such as telecommunications signaling, financial transactions, or industrial control systems, this vulnerability could result in significant business disruption and potential financial losses. The remote nature of the attack means that adversaries can exploit this flaw from outside the network perimeter without requiring any authentication or privileged access, making it particularly dangerous for systems that expose SCTP services to the internet. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and specifically targets the integrity and availability of system resources through kernel-level exploitation.
Mitigation strategies for CVE-2011-2482 primarily focus on applying the appropriate kernel security patches that were developed to address the null pointer dereference in the sctp_sock_migrate function. System administrators should immediately update their Red Hat Enterprise Linux 5 installations to include kernel versions 2.6.21 or later, which contain the necessary fixes for this vulnerability. Additionally, network administrators can implement firewall rules to block incoming SCTP traffic if the service is not required, though this approach should be weighed against business requirements for SCTP functionality. The vulnerability also highlights the importance of maintaining current security patches and conducting regular vulnerability assessments, as it represents a failure in timely patch management that allowed a known exploit to remain active in production environments for an extended period. Organizations should also consider implementing network monitoring solutions that can detect anomalous SCTP traffic patterns that may indicate exploitation attempts, providing an additional layer of defense against this specific class of denial of service attacks.