title: Junos OS: MX Series: Crafted packets traversing a Broadband Network Gateway (BNG) configured with IPv6 NDP proxy could lead to Denial of Service
description: Due to a new NDP proxy feature for EVPN leaf nodes introduced in Junos OS 17.4, crafted NDPv6 packets could transit a Junos device configured as a Broadband Network Gateway (BNG) and reach the EVPN leaf node, causing a stale MAC address entry. This could cause legitimate traffic to be discarded, leading to a Denial of Service (DoS) condition. This issue only affects Junos OS 17.4 and later releases. Prior releases do not support this feature and are unaffected by this vulnerability. This issue only affects IPv6. IPv4 ARP proxy is unaffected by this vulnerability. This issue affects Juniper Networks Junos OS: 17.4 versions prior to 17.4R2-S9, 17.4R3 on MX Series; 18.1 versions prior to 18.1R3-S9 on MX Series; 18.2 versions prior to 18.2R2-S7, 18.2R3-S3 on MX Series; 18.2X75 versions prior to 18.2X75-D33, 18.2X75-D411, 18.2X75-D420, 18.2X75-D60 on MX Series; 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3 on MX Series; 18.4 versions prior to 18.4R1-S5, 18.4R2-S2, 18.4R3 on MX Series; 19.1 versions prior to 19.1R1-S4, 19.1R2 on MX Series; 19.2 versions prior to 19.2R1-S3, 19.2R2 on MX Series.
problem types: CWE-20 Improper Input Validation
affected:
{
platforms: MX Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 17.4R2-S9, 17.4R3, status: affected, version: 17.4, versionType: custom
lessThan: 18.1R3-S9, status: affected, version: 18.1, versionType: custom
lessThan: 18.2R2-S7, 18.2R3-S3, status: affected, version: 18.2, versionType: custom
lessThan: 18.2X75-D33, 18.2X75-D411, 18.2X75-D420, 18.2X75-D60, status: affected, version: 18.2X75, versionType: custom
lessThan: 18.3R1-S7, 18.3R2-S3, 18.3R3, status: affected, version: 18.3, versionType: custom
lessThan: 18.4R1-S5, 18.4R2-S2, 18.4R3, status: affected, version: 18.4, versionType: custom
lessThan: 19.1R1-S4, 19.1R2, status: affected, version: 19.1, versionType: custom
lessThan: 19.2R1-S3, 19.2R2, status: affected, version: 19.2, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: ADJACENT_NETWORK
availabilityImpact: HIGH
baseScore: 7.4
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/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: 17.4R2-S9, 17.4R3, 18.1R3-S9, 18.2R2-S7, 18.2R3-S3, 18.2X75-D33, 18.2X75-D411, 18.2X75-D420, 18.2X75-D60, 18.3R1-S7, 18.3R2-S3, 18.3R3, 18.3R3-S1, 18.4R1-S5, 18.4R2-S2, 18.4R3, 19.1R1-S4, 19.1R2, 19.2R1-S3, 19.2R2, 19.3R1, 19.4R1, and all subsequent releases.
workarounds: Configure 'no-arp-suppression' to disable Proxy ARP/NDP feature.  For example:
[routing-instances <name> protocols evpn]
# set no-arp-suppression