CVE-2022-22202 in Junos OS
Summary
by MITRE • 07/20/2022
An Improper Handling of Exceptional Conditions vulnerability on specific PTX Series devices, including the PTX1000, PTX3000 (NextGen), PTX5000, PTX10002-60C, PTX10008, and PTX10016 Series, in Juniper Networks Junos OS allows an unauthenticated MPLS-based attacker to cause a Denial of Service (DoS) by triggering the dcpfe process to crash and FPC to restart. On affected PTX Series devices, processing specific MPLS packets received on an interface with multiple units configured may cause FPC to restart unexpectedly. Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue only affects PTX Series devices utilizing specific FPCs found on PTX1000, PTX3000 (NextGen), PTX5000, PTX10002-60C, PTX10008, and PTX10016 Series devices, only if multiple units are configured on the ingress interface, and at least one unit has 'family mpls' *not* configured. See the configuration sample below for more information. No other platforms are affected by this vulnerability. This issue affects: Juniper Networks Junos OS on PTX Series: All versions prior to 19.1R3-S9; 19.2 versions prior to 19.2R3-S6; 19.3 versions prior to 19.3R3-S6; 19.4 versions prior to 19.4R3-S8; 20.1 versions prior to 20.1R3-S4; 20.2 versions prior to 20.2R3-S5; 20.3 versions prior to 20.3R3-S4; 20.4 versions prior to 20.4R3-S4; 21.1 versions prior to 21.1R3-S2; 21.2 versions prior to 21.2R3-S1; 21.3 versions prior to 21.3R3; 21.4 versions prior to 21.4R2; 22.1 versions prior to 22.1R2.
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Analysis
by VulDB Data Team • 07/20/2022
This vulnerability represents a critical improper handling of exceptional conditions within the Juniper Networks Junos OS implementation on specific PTX Series devices. The flaw manifests as a denial of service condition that can be triggered by an unauthenticated attacker through the manipulation of MPLS packets, specifically targeting devices with certain hardware configurations. The vulnerability affects a narrow subset of Juniper's PTX Series platforms including the PTX1000, PTX3000 (NextGen), PTX5000, PTX10002-60C, PTX10008, and PTX10016 Series devices. The technical root cause lies in the dcpfe process which crashes when processing specific MPLS packets, leading to full FPC (Flexible PIC Concentrator) restarts that disrupt network services.
The operational impact of this vulnerability extends beyond simple service disruption to create sustained denial of service conditions that can persist as long as malicious packets continue to be processed. The attack vector specifically requires multiple units configured on the ingress interface, with at least one unit lacking the 'family mpls' configuration. This particular combination creates a condition where the system fails to properly handle exceptional circumstances during packet processing, resulting in process crashes and subsequent system restarts. The vulnerability demonstrates characteristics consistent with CWE-400, improper handling of exceptional conditions, and aligns with ATT&CK technique T1499.004 for network denial of service attacks.
Network administrators face significant operational challenges when addressing this vulnerability, as the attack requires no authentication and can be executed from any location capable of sending MPLS packets to the affected interfaces. The configuration requirements for exploitation create a specific attack surface that affects only devices meeting multiple criteria, but this targeted nature does not diminish the severity of impact. Organizations must carefully evaluate their device configurations to identify affected systems, particularly focusing on PTX Series devices with multiple interface units and specific MPLS configuration patterns. The vulnerability affects multiple Junos OS version streams across various release branches, requiring comprehensive patch management across all affected software versions.
The mitigation strategy involves implementing firmware updates to supported Junos OS versions that contain the necessary patches for this vulnerability. Organizations should prioritize patching affected devices according to their risk assessment and business continuity requirements. Additionally, network segmentation and access control measures can provide temporary protection while patches are deployed. The vulnerability highlights the importance of proper configuration management and the potential for seemingly innocuous configuration elements to create security weaknesses when combined with specific hardware platforms. Security teams should monitor their networks for signs of exploitation attempts and maintain awareness of the specific version ranges affected by this vulnerability.