CVE-2020-1602 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 IPv4 packets who may remotely take over the code execution of the JDHDCP process. This issue affect IPv4 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-2020-1602 represents a critical remote code execution flaw within Juniper Networks' Dynamic Host Configuration Protocol Daemon (JDHCPD) implementation on Junos OS and Junos OS Evolved systems. This security weakness specifically manifests when devices are configured to operate in DHCP relay mode, creating an attack surface that adversaries can exploit through carefully crafted IPv4 packets. The vulnerability stems from insufficient input validation and improper handling of DHCP relay messages within the JDHCPD process, allowing attackers to manipulate memory structures and potentially execute arbitrary code with the privileges of the JDHCPD service.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-787, concerning out-of-bounds write operations. When malicious packets are received by the JDHCPD process in relay mode, the daemon fails to properly validate packet contents and length specifications, leading to memory corruption that can be leveraged for code execution. The attack vector specifically targets IPv4 DHCP relay functionality, making it particularly dangerous for network infrastructure devices that rely on DHCP services for dynamic IP address allocation. This vulnerability operates at the network protocol level, where attackers can send malformed DHCP relay packets that trigger the buffer overflow condition within the JDHCPD daemon.
The operational impact of CVE-2020-1602 is severe and far-reaching for organizations utilizing affected Junos OS versions. Successful exploitation could result in complete compromise of network devices running vulnerable JDHCPD implementations, potentially allowing attackers to gain persistent access to critical network infrastructure. The vulnerability affects multiple release branches and versions across the Junos OS ecosystem, spanning from version 15.1 through 19.2, with specific patch levels required for each version line. Network administrators face the challenge of identifying all affected devices across their infrastructure, as the vulnerability can be exploited remotely without authentication, making it particularly dangerous in environments where network devices are accessible from untrusted networks or where DHCP services are exposed to external traffic.
Mitigation strategies for this vulnerability require immediate implementation of software patches provided by Juniper Networks, as recommended in their security advisories. Organizations should prioritize updating all affected Junos OS devices to the patched versions, with particular attention to devices configured in DHCP relay mode. Network segmentation and access control measures should be implemented to limit exposure of DHCP relay services to trusted networks only, while monitoring for anomalous DHCP traffic patterns that might indicate exploitation attempts. The vulnerability's classification under ATT&CK technique T1059.007 for command and scripting interpreter and T1021.001 for remote services suggests that exploitation could lead to further lateral movement within the network, making comprehensive network monitoring essential for detection and response activities. Additionally, organizations should consider disabling DHCP relay functionality on devices where it is not strictly required, as this would eliminate the attack surface entirely while maintaining network functionality through alternative configurations.