CVE-2008-2464 in FreeBSD
Summary
by MITRE
The mld_input function in sys/netinet6/mld6.c in the kernel in NetBSD 4.0, FreeBSD, and KAME, when INET6 is enabled, allows remote attackers to cause a denial of service (divide-by-zero error and panic) via a malformed ICMPv6 Multicast Listener Discovery (MLD) query with a certain Maximum Response Delay value.
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Analysis
by VulDB Data Team • 07/25/2024
The vulnerability described in CVE-2008-2464 represents a critical denial of service weakness affecting multiple operating systems including NetBSD 4.0, FreeBSD, and KAME implementations. This issue resides within the multicast listener discovery protocol handling mechanism specifically in the mld_input function located in the sys/netinet6/mld6.c kernel source file. The flaw manifests when the system processes malformed ICMPv6 Multicast Listener Discovery queries, which are essential components of IPv6 networking for managing multicast group memberships. The vulnerability is particularly concerning because it can be exploited remotely, allowing attackers to trigger system instability through carefully crafted network packets.
The technical root cause of this vulnerability stems from inadequate input validation within the mld_input function where the Maximum Response Delay field in MLD queries is not properly sanitized before processing. When an attacker sends a malformed MLD query containing a specific Maximum Response Delay value, the kernel code attempts to perform a division operation using this value without proper bounds checking. This leads to a divide-by-zero error that subsequently causes the kernel to panic and crash the entire system. The vulnerability is categorized under CWE-369 as a divide by zero condition, which represents a fundamental flaw in input validation and error handling within kernel space operations.
The operational impact of this vulnerability extends beyond simple service disruption as it can result in complete system crashes across affected platforms. Network administrators face significant challenges since the attack can be executed without requiring any authentication or privileged access, making it particularly dangerous in environments where network traffic is not strictly controlled. The affected systems include various versions of FreeBSD and NetBSD operating systems, which are widely used in enterprise networking equipment and server infrastructure. The panic condition triggered by this vulnerability can cause complete system downtime, requiring manual intervention and system reboot to restore normal operations.
Mitigation strategies for this vulnerability involve implementing immediate software updates and patches from the respective operating system vendors. System administrators should prioritize applying kernel updates that address the input validation flaw in the mld_input function to prevent exploitation. Network segmentation and firewall rules can be configured to limit ICMPv6 traffic, particularly MLD queries, from untrusted sources. Additionally, implementing intrusion detection systems that monitor for unusual ICMPv6 traffic patterns can help identify potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1499.001 which covers network denial of service attacks, and represents a classic example of how kernel-level input validation failures can be exploited for system compromise. Organizations should also consider implementing network monitoring solutions that can detect and alert on malformed ICMPv6 packets that may indicate attempted exploitation of this vulnerability.