CVE-2011-0716 in Linux
Summary
by MITRE
The br_multicast_add_group function in net/bridge/br_multicast.c in the Linux kernel before 2.6.38, when a certain Ethernet bridge configuration is used, allows local users to cause a denial of service (memory corruption and system crash) by sending IGMP packets to a local interface.
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability identified as CVE-2011-0716 resides within the Linux kernel's bridge multicast implementation, specifically in the br_multicast_add_group function located in net/bridge/br_multicast.c. This flaw affects Linux kernel versions prior to 2.6.38 and represents a critical security issue that can be exploited by local attackers to induce system crashes and memory corruption. The vulnerability manifests when particular Ethernet bridge configurations are employed, creating a condition where the kernel's multicast group management logic fails to properly validate incoming IGMP packets. The technical root cause stems from insufficient input validation and memory management within the multicast group addition process, which allows malformed or maliciously crafted IGMP traffic to trigger buffer overflows or invalid memory accesses.
The operational impact of this vulnerability extends beyond simple denial of service, as it can lead to complete system crashes and potential memory corruption that may compromise system stability and availability. Local users with access to the affected system can exploit this weakness by simply sending specially crafted IGMP packets to a local interface, requiring no network connectivity or external attack vectors. This makes the vulnerability particularly dangerous in environments where local access is possible, such as shared systems, development environments, or compromised machines where attackers might already have user-level access. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates how improper input validation in kernel space can result in system-wide failures. The attack pattern follows the ATT&CK technique T1499.004, which involves network denial of service attacks, though in this case the attack is executed locally rather than through network-based vectors.
The exploitation of CVE-2011-0716 requires minimal privileges and computational resources, making it a particularly attractive target for attackers seeking to disrupt system operations. When an attacker sends IGMP packets to a local interface configured in a specific bridge setup, the kernel's multicast handling code path becomes vulnerable to memory corruption. The br_multicast_add_group function fails to properly validate the group address or packet structure, leading to potential buffer overflows or use-after-free conditions in kernel memory. This type of vulnerability represents a classic example of how kernel-level programming errors can result in privilege escalation opportunities or system compromise. The vulnerability's impact is amplified in environments where bridge networking is actively used, such as in virtualization platforms, network infrastructure devices, or systems running containerized applications that utilize Linux bridge functionality for network isolation. System administrators should note that this vulnerability affects not only standalone systems but also complex network environments where multicast traffic is processed through bridge interfaces, potentially creating cascading failures in networked systems that rely on proper multicast handling for service discovery or streaming applications. The fix for this vulnerability required modifications to the kernel's multicast group management code to properly validate packet contents and ensure memory allocation boundaries are respected during group addition operations, demonstrating the importance of rigorous input validation in kernel space programming.