CVE-2018-0050 in Junos
Summary
by MITRE
An error handling vulnerability in Routing Protocols Daemon (RPD) of Juniper Networks Junos OS allows an attacker to cause RPD to crash. Continued receipt of this malformed MPLS RSVP packet will cause a sustained Denial of Service condition. Affected releases are Juniper Networks Junos OS: 14.1 versions prior to 14.1R8-S5, 14.1R9; 14.1X53 versions prior to 14.1X53-D48 on QFX Switching; 14.2 versions prior to 14.1X53-D130 on QFabric System; 14.2 versions prior to 14.2R4. This issue does not affect versions of Junos OS before 14.1R1. Junos OS RSVP only supports IPv4. IPv6 is not affected by this issue. This issue require it to be received on an interface configured to receive this type of traffic.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability described in CVE-2018-0050 represents a critical error handling flaw within the Routing Protocols Daemon (RPD) component of Juniper Networks Junos OS operating systems. This issue specifically targets the processing of MPLS RSVP (Resource Reservation Protocol) packets, which are essential for establishing and maintaining quality of service connections in network infrastructure. The vulnerability manifests as improper handling of malformed MPLS RSVP packets, leading to unexpected daemon crashes and subsequent denial of service conditions that can severely impact network operations and reliability.
The technical nature of this flaw falls under CWE-248, which describes an "Uncaught Exception" scenario where the RPD daemon fails to properly validate incoming MPLS RSVP packet structures. When malformed packets are received, the daemon does not implement adequate error recovery mechanisms, causing it to terminate unexpectedly and restart. This behavior creates a cascading effect where continued receipt of such malformed packets results in sustained denial of service conditions, effectively disrupting routing services and potentially causing network outages. The vulnerability specifically affects IPv4 implementations within Junos OS, as RSVP support is limited to IPv4 addressing, making IPv6 implementations immune to this particular flaw.
From an operational impact perspective, this vulnerability presents a significant risk to network infrastructure stability and availability. The attack vector requires that malicious packets be received on interfaces specifically configured to process RSVP traffic, limiting the attack surface but not eliminating the threat. Network administrators must understand that even a single compromised interface could potentially cause widespread routing disruption throughout the affected network segment. The sustained denial of service condition means that once triggered, the impact persists until the system is manually restarted or the vulnerable daemon is patched, creating extended periods of network instability that can affect critical business operations and services.
The remediation approach for CVE-2018-0050 requires immediate implementation of vendor-provided security patches and updates for all affected Junos OS versions. Organizations should prioritize patching systems running versions prior to the specified safe releases including 14.1R8-S5, 14.1R9, 14.1X53-D48, and 14.2R4, while also ensuring proper network segmentation to limit exposure to only necessary interfaces. Network monitoring should be enhanced to detect unusual packet patterns and daemon restart events that may indicate exploitation attempts. Additionally, implementing ingress filtering and access control lists to restrict RSVP traffic to trusted sources can provide additional layers of protection. This vulnerability aligns with ATT&CK technique T1499.002 which covers "Endpoint Denial of Service" and demonstrates the importance of proper error handling in network infrastructure components to maintain system resilience against crafted packet attacks.