title: Junos OS: Remote code execution vulnerability in overlayd service
description: A buffer size validation vulnerability in the overlayd service of Juniper Networks Junos OS may allow an unauthenticated remote attacker to send specially crafted packets to the device, triggering a partial Denial of Service (DoS) condition, or leading to remote code execution (RCE). Continued receipt and processing of these packets will sustain the partial DoS. The overlayd daemon handles Overlay OAM packets, such as ping and traceroute, sent to the overlay. The service runs as root by default and listens for UDP connections on port 4789. This issue results from improper buffer size validation, which can lead to a buffer overflow. Unauthenticated attackers can send specially crafted packets to trigger this vulnerability, resulting in possible remote code execution. overlayd runs by default in MX Series, ACX Series, and QFX Series platforms. The SRX Series does not support VXLAN and is therefore not vulnerable to this issue. Other platforms are also vulnerable if a Virtual Extensible LAN (VXLAN) overlay network is configured. This issue affects Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R2-S13, 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R2-S2, 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R3-S1; 19.4 versions prior to 19.4R2-S4, 19.4R3-S1; 20.1 versions prior to 20.1R2-S1, 20.1R3; 20.2 versions prior to 20.2R2, 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1.
problem types: CWE-131 Incorrect Calculation of Buffer Size
affected:
{
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 15.1R7-S9, status: affected, version: 15.1, versionType: custom
lessThan: 17.3R3-S11, status: affected, version: 17.3, versionType: custom
lessThan: 17.4R2-S13, 17.4R3-S4, status: affected, version: 17.4, versionType: custom
lessThan: 18.1R3-S12, status: affected, version: 18.1, versionType: custom
lessThan: 18.2R2-S8, 18.2R3-S7, status: affected, version: 18.2, versionType: custom
lessThan: 18.3R3-S4, status: affected, version: 18.3, versionType: custom
lessThan: 18.4R1-S8, 18.4R2-S7, 18.4R3-S7, status: affected, version: 18.4, versionType: custom
lessThan: 19.1R2-S2, 19.1R3-S4, status: affected, version: 19.1, versionType: custom
lessThan: 19.2R1-S6, 19.2R3-S2, status: affected, version: 19.2, versionType: custom
lessThan: 19.3R3-S1, status: affected, version: 19.3, versionType: custom
lessThan: 19.4R2-S4, 19.4R3-S1, status: affected, version: 19.4, versionType: custom
lessThan: 20.1R2-S1, 20.1R3, status: affected, version: 20.1, versionType: custom
lessThan: 20.2R2, 20.2R2-S1, 20.2R3, status: affected, version: 20.2, versionType: custom
lessThan: 20.3R1-S1, status: affected, version: 20.3, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 9.8
baseSeverity: CRITICAL
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
version: 3.1
]
exploits: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
solutions: The following software releases have been updated to resolve this specific issue: Junos OS 15.1X49-D240,  15.1R7-S9, 17.3R3-S11, 17.4R2-S13, 17.4R3-S4, 18.1R3-S12, 18.2R2-S8, 18.2R3-S7, 18.3R3-S4, 18.4R1-S8, 18.4R2-S7, 18.4R3-S7, 19.1R2-S2, 19.1R3-S4, 19.2R1-S6, 19.2R3-S2, 19.3R3-S1, 19.4R2-S4, 19.4R3-S1, 20.1R2-S1, 20.1R3, 20.2R2, 20.2R2-S1, 20.2R3, 20.3R1-S1, 20.4R1, and all subsequent releases.
This fix has also been proactively committed into other releases that might not be vulnerable to this issue.
workarounds: Two methods exist to mitigate this issue:
1. Limit the exploitable attack surface of critical infrastructure networking equipment by using access lists or firewall filters to limit access to the device via UDP only from trusted, administrative networks or hosts.
2. Disable Overlay OAM packet via the configuration command: 'set system processes overlay-ping-traceroute disable'