CVE-2018-0030 in Junos
Summary
by MITRE
Receipt of a specific MPLS packet may cause MPC7/8/9, PTX-FPC3 (FPC-P1, FPC-P2) line cards or PTX1K to crash and restart. By continuously sending specific MPLS packets, an attacker can repeatedly crash the line cards or PTX1K causing a sustained Denial of Service. Affected releases are Juniper Networks Junos OS with MPC7/8/9 or PTX-FPC3 (FPC-P1, FPC-P2) installed and PTX1K: 15.1F versions prior to 15.1F6-S10; 15.1 versions prior to 15.1R4-S9, 15.1R6-S6, 15.1R7; 16.1 versions prior to 16.1R3-S8, 16.1R4-S9, 16.1R5-S4, 16.1R6-S3, 16.1R7; 16.1X65 versions prior to 16.1X65-D46; 16.2 versions prior to 16.2R1-S6, 16.2R2-S5, 16.2R3; 17.1 versions prior to 17.1R1-S7, 17.1R2-S7, 17.1R3; 17.2 versions prior to 17.2R1-S4, 17.2R2-S4, 17.2R3; 17.2X75 versions prior to 17.2X75-D70, 17.2X75-D90; 17.3 versions prior to 17.3R1-S4, 17.3R2, 17.4 versions prior to 17.4R1-S2, 17.4R2. Refer to KB25385 for more information about PFE line cards.
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Analysis
by VulDB Data Team • 04/06/2023
This vulnerability affects Juniper Networks routers running specific line card hardware including MPC7/8/9 platforms and PTX-FPC3 (FPC-P1, FPC-P2) as well as PTX1K devices. The flaw manifests when these systems receive specially crafted MPLS packets that trigger a system crash and subsequent restart of the affected line cards. The vulnerability represents a significant security concern as it can be exploited to create persistent denial of service conditions that severely impact network availability and reliability.
The technical root cause of this vulnerability lies in the improper handling of specific MPLS packet structures within the Packet Forwarding Engine (PFE) of the affected hardware platforms. When the system processes these malformed MPLS packets, the packet processing logic fails to properly validate or handle the packet headers, leading to an unexpected system state that results in a crash. This behavior aligns with CWE-129, which describes improper validation of input boundaries, and CWE-248, which addresses an exception not caught by the application. The vulnerability specifically impacts the forwarding plane processing capabilities of the network equipment, causing the system to enter a restart loop that can only be terminated by manual intervention or system reboot.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential business continuity risks for organizations relying on Juniper network infrastructure. An attacker capable of sending these specific MPLS packets can repeatedly crash the affected line cards, creating sustained denial of service conditions that can persist until the system is manually restarted or the firmware is updated. The vulnerability affects multiple software versions across different Junos OS release lines, indicating a widespread issue that requires careful attention from network administrators. According to the ATT&CK framework, this vulnerability maps to T1499.004, which covers network disruption attacks, and T1595.001, which involves network infiltration through reconnaissance and exploitation of system vulnerabilities.
The exploitation of this vulnerability follows a straightforward pattern where an attacker sends specifically crafted MPLS packets to the target router, causing immediate system instability and restart. The sustained nature of the denial of service means that even after a single crash, the system will continue to restart upon receiving additional malformed packets, making the attack persistent until mitigations are applied. Network administrators must understand that this vulnerability affects not only the primary routing functionality but also the line card hardware itself, which can lead to complete service outages in network segments that depend on the affected platforms. The vulnerability requires careful monitoring and immediate patching to prevent exploitation, as the affected releases span multiple major and minor Junos OS versions, indicating the need for comprehensive vulnerability management across different network infrastructure components. Organizations should also consider implementing network segmentation and access control measures to limit potential attack vectors and reduce the risk of unauthorized access to network devices that could be exploited to deliver these malicious MPLS packets.