CVE-2024-20464 in IOS XE
Summary
by MITRE • 09/25/2024
A vulnerability in the Protocol Independent Multicast (PIM) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to insufficient validation of received IPv4 PIMv2 packets. An attacker could exploit this vulnerability by sending a crafted PIMv2 packet to a PIM-enabled interface on an affected device. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition.
Note: This vulnerability can be exploited with either an IPv4 multicast or unicast packet.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2024-20464 resides within the Protocol Independent Multicast PIM implementation of Cisco IOS XE Software, representing a critical security weakness that undermines network infrastructure stability. This flaw manifests as insufficient input validation mechanisms within the PIMv2 packet processing pipeline, creating an exploitable condition that affects devices operating with PIM enabled. The vulnerability specifically targets the IPv4 PIMv2 packet handling routines where malformed or crafted packets can bypass normal validation procedures. Network administrators must understand that this issue impacts not only the core routing functionality but also the overall availability of network services through potential device reloads.
The technical exploitation of this vulnerability occurs through the manipulation of PIMv2 packet structures that traverse PIM-enabled interfaces on affected Cisco devices. Attackers can craft malicious packets containing malformed fields or unexpected packet sequences that the software fails to properly validate before processing. The absence of comprehensive input sanitization allows these crafted packets to trigger internal state inconsistencies or buffer handling errors within the PIM processing modules. This particular flaw demonstrates characteristics consistent with CWE-129 Input Validation and CWE-787 Out-of-bounds Write, where insufficient validation leads to memory corruption scenarios that ultimately result in device instability. The attack vector requires no authentication credentials and can be executed from remote locations, making it particularly dangerous for network infrastructure components that must remain accessible to external traffic.
Operational impact assessment reveals that successful exploitation of CVE-2024-20464 can result in complete service disruption across affected network segments. When triggered, the vulnerability causes the targeted device to undergo an automatic reload process, effectively removing it from network operations until manual intervention or automatic recovery occurs. This DoS condition creates cascading effects throughout the network topology as routing decisions become disrupted and alternative paths must be computed. The vulnerability's ability to be exploited via both multicast and unicast packets significantly increases its attack surface, as attackers can leverage either traffic type to initiate the exploit. Organizations running Cisco IOS XE software on routers, switches, and other network devices that support PIM functionality face substantial risk of service interruption, particularly in environments where high availability and continuous network operation are critical requirements.
Mitigation strategies for this vulnerability should prioritize immediate software updates from Cisco, specifically targeting the patches released to address the PIM validation deficiencies. Network administrators should implement ingress filtering and access control lists to restrict PIM traffic from untrusted sources, particularly on interfaces where PIM is not required. The deployment of network monitoring solutions capable of detecting anomalous PIM packet patterns can provide early warning capabilities before full exploitation occurs. Additionally, implementing redundant network paths and ensuring proper failover mechanisms can help minimize the impact of potential DoS events. Security teams should also consider disabling PIM functionality on devices where it is not strictly necessary, following the principle of least privilege for network protocols. These measures align with ATT&CK technique T1499.004 for Network Denial of Service and should be integrated into broader network security monitoring frameworks to detect and prevent similar exploitation patterns across the enterprise infrastructure.