CVE-2020-1609 in Junos
Summary
by MITRE
When a device using Juniper Network's Dynamic Host Configuration Protocol Daemon (JDHCPD) process on Junos OS or Junos OS Evolved which is configured in relay mode it vulnerable to an attacker sending crafted IPv6 packets who may then arbitrarily execute commands as root on the target device. This issue affects IPv6 JDHCPD services. This issue affects: Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S6; 15.1X49 versions prior to 15.1X49-D200; 15.1X53 versions prior to 15.1X53-D592; 16.1 versions prior to 16.1R7-S6; 16.2 versions prior to 16.2R2-S11; 17.1 versions prior to 17.1R2-S11, 17.1R3-S1; 17.2 versions prior to 17.2R2-S8, 17.2R3-S3; 17.3 versions prior to 17.3R3-S6; 17.4 versions prior to 17.4R2-S7, 17.4R3; 18.1 versions prior to 18.1R3-S8; 18.2 versions prior to 18.2R3-S2; 18.2X75 versions prior to 18.2X75-D60; 18.3 versions prior to 18.3R1-S6, 18.3R2-S2, 18.3R3; 18.4 versions prior to 18.4R1-S5, 18.4R2-S3, 18.4R3; 19.1 versions prior to 19.1R1-S3, 19.1R2; 19.2 versions prior to 19.2R1-S3, 19.2R2*. and All versions prior to 19.3R1 on Junos OS Evolved. This issue do not affect versions of Junos OS prior to 15.1, or JDHCPD operating as a local server in non-relay mode.
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Analysis
by VulDB Data Team • 03/24/2024
The vulnerability identified as CVE-2020-1609 represents a critical remote code execution flaw within Juniper Networks' Dynamic Host Configuration Protocol Daemon (JDHCPD) implementation when operating in relay mode on Junos OS and Junos OS Evolved systems. This vulnerability specifically targets IPv6 JDHCPD services and exploits a flaw in how the daemon processes crafted IPv6 packets, enabling attackers to execute arbitrary commands with root privileges on affected devices. The flaw stems from insufficient input validation and improper handling of malformed IPv6 packet structures within the relay mode implementation, creating a pathway for privilege escalation and full system compromise.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and relates to improper input validation mechanisms within network protocol processing. Attackers can leverage this weakness by sending specifically crafted IPv6 packets to the vulnerable JDHCPD service, bypassing normal authentication and authorization controls. The exploitation process typically involves crafting packets that trigger memory corruption within the daemon's processing routines, ultimately allowing attackers to inject and execute malicious code with the highest system privileges. This represents a severe operational risk as it eliminates the need for prior authentication credentials and provides complete control over the affected network infrastructure.
The operational impact of CVE-2020-1609 extends beyond simple system compromise, as it fundamentally undermines network security posture and can lead to widespread disruption of network services. Organizations running affected Junos OS versions in relay mode face potential data exfiltration, network infiltration, and complete loss of device control. The vulnerability affects a broad range of Junos OS versions across multiple release branches, with specific patched versions identified for each major release line. The attack surface is particularly concerning given that JDHCPD operates as a core network service daemon that is typically exposed to external networks through relay configurations, making it accessible to remote attackers. This vulnerability also maps to ATT&CK technique T1059.007 for command and script interpreter, specifically focusing on the execution of commands through network services.
Mitigation strategies for CVE-2020-1609 require immediate implementation of vendor-provided security patches across all affected Junos OS versions, with particular attention to systems operating in relay mode. Network administrators should prioritize patching devices running affected versions of Junos OS, ensuring that all identified vulnerable release branches receive the appropriate security updates. Additional defensive measures include implementing network segmentation to limit exposure of JDHCPD services to untrusted networks, disabling IPv6 relay functionality where not required, and monitoring network traffic for suspicious IPv6 packet patterns that may indicate exploitation attempts. Organizations should also consider implementing intrusion detection systems capable of identifying crafted packet patterns associated with this vulnerability. The remediation process must include thorough testing of patches in controlled environments before deployment to production systems to prevent potential service disruption. Security teams should conduct comprehensive vulnerability assessments to identify all devices running affected Junos OS versions and ensure proper configuration management practices are implemented to prevent future exposure to similar vulnerabilities.