CVE-2013-3077 in FreeBSD
Summary
by MITRE
Multiple integer overflows in the IP_MSFILTER and IPV6_MSFILTER features in (1) sys/netinet/in_mcast.c and (2) sys/netinet6/in6_mcast.c in the multicast implementation in the kernel in FreeBSD 8.3 through 9.2-PRERELEASE allow local users to bypass intended restrictions on kernel-memory read and write operations, and consequently gain privileges, via vectors involving a large number of source-filter entries.
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Analysis
by VulDB Data Team • 05/21/2021
The vulnerability identified as CVE-2013-3077 represents a critical integer overflow flaw within the multicast implementation of FreeBSD kernel versions 8.3 through 9.2-PRERELEASE. This issue specifically affects the IP_MSFILTER and IPV6_MSFILTER features that govern multicast group membership and source filtering operations. The flaw resides in two primary kernel source files: sys/netinet/in_mcast.c and sys/netinet6/in6_mcast.c, which handle multicast operations for both IPv4 and IPv6 protocols respectively. These components are fundamental to network communication systems that rely on multicast routing and filtering mechanisms.
The technical exploitation of this vulnerability stems from improper handling of integer values when processing source-filter entries in multicast group memberships. When a large number of source-filter entries are processed, the integer overflow conditions cause the kernel to miscalculate memory allocation sizes and buffer boundaries. This miscalculation results in memory corruption that can be leveraged by local attackers to bypass kernel memory protection mechanisms. The overflow conditions occur during the validation and processing of multicast filter structures where the kernel fails to properly validate the size parameters of source-filter arrays before allocating memory or performing memory operations.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential kernel memory read and write operations that should be restricted to authorized processes. Attackers can exploit these integer overflows to manipulate kernel memory structures, potentially leading to arbitrary code execution with kernel-level privileges. The local nature of the attack means that an attacker must already have access to the system, but the privilege escalation capability makes this vulnerability particularly dangerous as it can be used to gain complete system control. The vulnerability affects the core multicast functionality that is essential for various network services including streaming media, network monitoring, and distributed application communication.
This vulnerability maps directly to CWE-190, Integer Overflow or Wraparound, which classifies the issue as a fundamental flaw in integer arithmetic handling within kernel space operations. The attack pattern aligns with ATT&CK technique T1068, Exploitation for Privilege Escalation, where local users leverage kernel vulnerabilities to gain elevated privileges. The exploitation pathway demonstrates characteristics of T1059, Command and Scripting Interpreter, as attackers may need to execute specific commands to trigger the integer overflow conditions. Security practitioners should note that this vulnerability represents a classic example of how improper input validation in kernel space can lead to complete system compromise, highlighting the critical importance of robust memory management in operating system kernels.
Mitigation strategies for CVE-2013-3077 require immediate patching of affected FreeBSD systems to version 9.2-STABLE or later, where the integer overflow conditions have been properly addressed. System administrators should also implement network monitoring to detect unusual multicast traffic patterns that might indicate exploitation attempts. Additional protective measures include restricting local user access where possible and implementing proper privilege separation for multicast operations. The vulnerability underscores the necessity of regular kernel security updates and comprehensive testing of security patches before deployment in production environments to prevent exploitation of similar integer overflow conditions in other kernel subsystems.