CVE-2022-22249 in Junos OS
Summary
by MITRE • 10/18/2022
An Improper Control of a Resource Through its Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series allows an unauthenticated adjacent attacker to cause a Denial of Service (DoS). When there is a continuous mac move a memory corruption causes one or more FPCs to crash and reboot. These MAC moves can be between two local interfaces or between core/EVPN and local interface. The below error logs can be seen in PFE syslog when this issue happens: xss_event_handler(1071): EA[0:0]_PPE 46.xss[0] ADDR Error. ppe_error_interrupt(4298): EA[0:0]_PPE 46 Errors sync xtxn error xss_event_handler(1071): EA[0:0]_PPE 1.xss[0] ADDR Error. ppe_error_interrupt(4298): EA[0:0]_PPE 1 Errors sync xtxn error xss_event_handler(1071): EA[0:0]_PPE 2.xss[0] ADDR Error. This issue affects Juniper Networks Junos OS on MX Series: All versions prior to 15.1R7-S13; 19.1 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 19.4R2-S7, 19.4R3-S8; 20.1 version 20.1R1 and later versions; 20.2 versions prior to 20.2R3-S5; 20.3 versions prior to 20.3R3-S5; 20.4 versions prior to 20.4R3-S2; 21.1 versions prior to 21.1R3; 21.2 versions prior to 21.2R3; 21.3 versions prior to 21.3R2.
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Analysis
by VulDB Data Team • 10/18/2022
This vulnerability represents a critical improper control of a resource through its lifetime flaw within the Packet Forwarding Engine of Juniper Networks Junos OS running on MX Series routers. The issue stems from inadequate resource management during mac move operations, creating a condition where continuous mac movements trigger memory corruption within the Forwarding Processing Card (FPC) components. This fundamental weakness allows an unauthenticated adjacent attacker to exploit the system through local network access, making it particularly dangerous in environments where physical or logical network proximity can be achieved by adversaries.
The technical exploitation mechanism involves sustained mac move operations that occur between local interfaces or between core/EVPN and local interfaces, creating a memory corruption scenario that ultimately results in FPC crashes and system reboots. The vulnerability manifests through specific error messages appearing in the PFE syslog including xss_event_handler errors with ADDR Error and ppe_error_interrupt messages indicating sync xtxn errors. These error patterns indicate that the system's memory management routines fail to properly handle the resource lifecycle during active mac move scenarios, leading to address errors that propagate through the PPE (Packet Processing Engine) components.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a persistent DoS condition that can severely impact network availability and reliability. When FPCs crash and reboot, network traffic experiences complete interruption across affected routing platforms, potentially causing cascading failures in larger network infrastructures. The vulnerability affects multiple Junos OS versions across different release branches, indicating a widespread issue that spans several years of product development and deployment cycles, making it particularly concerning for organizations with extensive MX Series deployments.
Organizations should prioritize immediate mitigation through firmware updates to supported versions that contain the necessary patches addressing the memory corruption issue. The vulnerability aligns with CWE-404, improper resource management, and falls under ATT&CK technique T1499.004 for endpoint denial of service. Network administrators should also implement monitoring solutions to detect unusual mac move patterns that could indicate exploitation attempts. Additional mitigations include restricting local network access to affected devices, implementing network segmentation to limit adjacent attacker access, and establishing robust alerting mechanisms for the specific error patterns mentioned in the vulnerability description. The patching strategy must account for potential compatibility issues with existing network configurations and ensure thorough testing in production environments before deployment.