CVE-2013-4686 in Junos
Summary
by MITRE
The kernel in Juniper Junos 10.4 before 10.4R14, 11.4 before 11.4R8, 11.4X27 before 11.4X27.43, 12.1 before 12.1R6, 12.1X44 before 12.1X44-D20, 12.2 before 12.2R4, and 12.3 before 12.3R2, in certain VLAN configurations with unrestricted arp-resp and proxy-arp settings, allows remote attackers to cause a denial of service (device crash) via a crafted ARP request, aka PR 842091.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability described in CVE-2013-4686 represents a critical denial of service flaw within the Juniper Junos operating system kernel. This weakness specifically manifests in devices running various versions of Junos software where certain VLAN configurations are implemented alongside unrestricted arp-resp and proxy-arp settings. The vulnerability operates through a carefully crafted ARP request that, when processed by the affected kernel, triggers a device crash leading to complete service disruption. This issue affects multiple release branches of Junos including 10.4, 11.4, 12.1, and 12.2 versions, with specific patch levels required to mitigate the risk. The flaw demonstrates a fundamental weakness in how the kernel handles ARP packet processing under certain network configuration conditions, making it particularly dangerous in production environments where network availability is paramount.
The technical implementation of this vulnerability stems from improper validation and handling of ARP responses within the kernel's network stack. When a device is configured with unrestricted arp-resp and proxy-arp functionality, the kernel's ARP processing module fails to properly validate incoming ARP requests before attempting to respond to them. This lack of input sanitization creates a condition where maliciously crafted ARP packets can exploit memory handling routines within the kernel, causing buffer overflows or invalid memory access patterns that ultimately result in system crashes. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the specific mechanism involves kernel memory corruption rather than traditional user-space buffer issues. The attack vector requires only network access to send the malicious ARP packet, making it particularly dangerous as it can be exploited remotely without requiring physical access or authentication credentials.
The operational impact of CVE-2013-4686 extends far beyond simple service disruption, as it can lead to complete network outages in environments where Junos devices serve as core network infrastructure. Network administrators may experience cascading failures as affected devices crash and restart, potentially disrupting routing, switching, and security functions across the entire network segment. The vulnerability affects network availability and reliability, which can have severe consequences for business operations, particularly in mission-critical environments such as financial services, telecommunications, or industrial control systems. Organizations may face extended downtime while implementing patches, potentially leading to service level agreement violations and significant financial losses. The remote exploit nature means that attackers can target multiple devices simultaneously, amplifying the potential impact and making this vulnerability particularly attractive for coordinated attacks against network infrastructure.
Mitigation strategies for CVE-2013-4686 require immediate implementation of software patches provided by Juniper, specifically targeting the affected versions mentioned in the advisory. Organizations should prioritize updating their Junos devices to the patched versions, with particular attention to the release levels indicated in the CVE description. Network administrators should also consider implementing temporary workarounds such as disabling proxy-arp and arp-resp functionality on affected VLAN configurations until patches can be deployed. The remediation process should include thorough testing in non-production environments before rolling out updates to production systems. Additionally, network monitoring should be enhanced to detect unusual ARP traffic patterns that may indicate exploitation attempts, and security teams should implement network segmentation strategies to limit the potential impact of successful attacks. This vulnerability aligns with ATT&CK technique T1499.001 for network denial of service attacks, making it a critical target for defensive security measures and incident response planning.