CVE-2020-1682 in Junos
Summary
by MITRE • 10/17/2020
An input validation vulnerability exists in Juniper Networks Junos OS, allowing an attacker to crash the srxpfe process, causing a Denial of Service (DoS) through the use of specific maintenance commands. The srxpfe process restarts automatically, but continuous execution of the commands could lead to an extended Denial of Service condition. This issue only affects the SRX1500, SRX4100, SRX4200, NFX150, NFX250, and vSRX-based platforms. No other products or platforms are affected by this vulnerability. This issue affects Juniper Networks Junos OS: 15.1X49 versions prior to 15.1X49-D220 on SRX1500, SRX4100, SRX4200, vSRX; 17.4 versions prior to 17.4R3-S3 on SRX1500, SRX4100, SRX4200, vSRX; 18.1 versions prior to 18.1R3-S11 on SRX1500, SRX4100, SRX4200, vSRX, NFX150; 18.2 versions prior to 18.2R3-S5 on SRX1500, SRX4100, SRX4200, vSRX, NFX150, NFX250; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3 on SRX1500, SRX4100, SRX4200, vSRX, NFX150, NFX250; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4 on SRX1500, SRX4100, SRX4200, vSRX, NFX150, NFX250; 19.1 versions prior to 19.1R3-S2 on SRX1500, SRX4100, SRX4200, vSRX, NFX150, NFX250; 19.2 versions prior to 19.2R1-S5, 19.2R3 on SRX1500, SRX4100, SRX4200, vSRX, NFX150, NFX250. This issue does not affect Junos OS 19.3 or any subsequent version.
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Analysis
by VulDB Data Team • 11/20/2020
The vulnerability described in CVE-2020-1682 represents a critical input validation flaw within Juniper Networks Junos OS that specifically targets the srxpfe process responsible for packet forwarding and processing on certain SRX and NFX platform models. This issue stems from inadequate validation of maintenance commands that can be executed against the system, allowing malicious actors to craft specially formatted inputs that trigger unexpected behavior in the forwarding engine. The vulnerability manifests as a controlled crash of the srxpfe process, which serves as a fundamental component for handling network traffic on these platforms. The flaw exists in the way the system processes specific maintenance commands, where improper input handling leads to memory corruption or invalid state transitions that ultimately cause the process to terminate unexpectedly. This represents a classic example of a buffer over-read or improper input validation scenario that can be exploited to achieve denial of service conditions.
The technical exploitation of this vulnerability occurs through the deliberate execution of maintenance commands that contain malformed or specially crafted parameters designed to trigger the input validation failure. When these commands are processed by the srxpfe component, the system fails to properly validate the input data before proceeding with processing, leading to an abrupt termination of the process. The affected platforms include SRX1500, SRX4100, SRX4200, NFX150, NFX250, and vSRX devices, all of which share the same vulnerable code path in their Junos OS implementations. The specific versions affected span multiple release branches including 15.1X49, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, and 19.2, indicating that this flaw has persisted across several major releases and represents a long-standing issue in the codebase. The vulnerability is particularly concerning because it affects the core forwarding functionality of these network devices, potentially disrupting network connectivity and service availability for extended periods.
The operational impact of CVE-2020-1682 extends beyond simple service disruption as it can be leveraged to create sustained denial of service conditions that may require manual intervention to resolve. While the srxpfe process does restart automatically upon crashing, the continuous execution of the malicious commands can lead to a cascading effect where the system remains in a state of constant restart cycles, effectively rendering the device unusable for its intended network security functions. This behavior creates a significant operational burden for network administrators who must monitor and potentially manually intervene to restore service, especially in environments where these devices serve as critical security gateways. The vulnerability's impact is particularly severe in high-availability environments where the automatic restart mechanism may not be sufficient to prevent extended service outages, potentially leading to complete network disruption for organizations relying on these platforms. The attack surface is further expanded by the fact that these devices are commonly deployed in perimeter security roles, making them attractive targets for adversaries seeking to disrupt network operations.
Organizations affected by this vulnerability should prioritize immediate remediation through the application of Juniper's official security patches and firmware updates for all impacted platforms. The vulnerability aligns with CWE-20, which describes improper input validation as a fundamental weakness that can lead to various security issues including denial of service conditions. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1499.004, which involves network disruption through denial of service attacks, and represents a low-effort method for achieving service disruption against network infrastructure. The remediation process should include comprehensive testing of patched firmware versions in non-production environments before deployment to production systems to ensure compatibility and prevent unintended service disruptions. Network administrators should also implement monitoring solutions to detect potential exploitation attempts and establish incident response procedures to quickly address any successful attacks. Additionally, organizations should consider implementing access controls and command restrictions on maintenance interfaces to limit the potential impact of such vulnerabilities, particularly in environments where privileged access to maintenance commands cannot be adequately restricted. The vulnerability's persistence across multiple release branches underscores the importance of maintaining current security patches and following vendor security advisories to protect against known weaknesses in network infrastructure platforms.