CVE-2022-22159 in Junos OS
Summary
by MITRE • 01/19/2022
A vulnerability in the NETISR network queue functionality of Juniper Networks Junos OS kernel allows an attacker to cause a Denial of Service (DoS) by sending crafted genuine packets to a device. During an attack, the routing protocol daemon (rpd) CPU may reach 100% utilization, yet FPC CPUs forwarding traffic will operate normally. This attack occurs when the attackers' packets are sent over an IPv4 unicast routing equal-cost multi-path (ECMP) unilist selection. Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition. An indicator of compromise may be to monitor NETISR drops in the network with the assistance of JTAC. Please contact JTAC for technical support for further guidance. This issue affects: Juniper Networks Junos OS 17.3 version 17.3R3-S9 and later versions prior to 17.3R3-S12; 17.4 version 17.4R3-S3 and later versions prior to 17.4R3-S5; 18.1 version 18.1R3-S11 and later versions prior to 18.1R3-S13; 18.2 version 18.2R3-S6 and later versions; 18.3 version 18.3R3-S4 and later versions prior to 18.3R3-S5; 18.4 version 18.4R3-S5 and later versions prior to 18.4R3-S9; 19.1 version 19.1R3-S3 and later versions prior to 19.1R3-S7. This issue does not affect Juniper Networks Junos OS versions prior to 17.3R3-S9. This issue does not affect Juniper Networks Junos OS Evolved.
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Analysis
by VulDB Data Team • 01/20/2022
This vulnerability resides within the NETISR network queue functionality of Juniper Networks Junos OS kernel, representing a significant denial of service threat that exploits specific routing protocol behaviors. The flaw manifests when crafted genuine packets are transmitted over IPv4 unicast routing with equal-cost multi-path unilist selection, creating a condition where the routing protocol daemon (rpd) consumes 100% CPU utilization while forwarding plane CPUs continue normal operations. This asymmetric impact on system resources creates a unique attack vector that specifically targets the control plane processing capabilities of the device.
The technical implementation of this vulnerability involves the manipulation of routing protocol packet processing within the kernel's network interrupt handling system. According to CWE classification, this represents a weakness in the design or implementation of network packet processing mechanisms, specifically related to resource exhaustion through improper handling of legitimate traffic patterns. The attack leverages the ECMP unilist selection mechanism to create sustained processing overhead that gradually consumes available CPU resources in the routing protocol daemon. This behavior aligns with ATT&CK technique T1499.004 for network denial of service, where adversaries target system resources to disrupt normal operations.
The operational impact of this vulnerability extends beyond simple service disruption as it creates a sustained condition that can persist until manual intervention occurs. Network administrators must monitor for specific indicators of compromise including unusual NETISR drop patterns, which serve as early warning signals for potential exploitation. The targeted versions span multiple Junos OS releases including 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, and 19.1 branches, indicating this issue affects a substantial portion of the Juniper OS ecosystem. The vulnerability specifically excludes versions prior to 17.3R3-S9 and does not impact Junos OS Evolved platforms, suggesting the flaw is tied to particular kernel implementations within the traditional Junos OS architecture.
Mitigation strategies should focus on immediate patching of affected versions to address the root cause within the kernel's packet processing logic. Network monitoring should emphasize tracking NETISR drop statistics as recommended by JTAC support protocols, enabling proactive detection of exploitation attempts. System administrators should consider implementing traffic filtering rules to limit the specific packet patterns that trigger the vulnerability while maintaining normal network operations. The vulnerability's nature suggests that temporary workarounds may be insufficient for long-term protection, requiring comprehensive version upgrades to patched releases. Security teams should also implement continuous monitoring for anomalous CPU utilization patterns in routing protocol daemons as part of their defensive posture against similar kernel-level resource exhaustion attacks.