title: Junos OS: EX4600, QFX5K Series: Stateless firewall filter matching 'user-vlan-id' will cause incomplete discard action
description: When configuring stateless firewall filters in Juniper Networks EX4600 and QFX 5000 Series devices using Virtual Extensible LAN protocol (VXLAN), the discard action will fail to discard traffic under certain conditions. Given a firewall filter configuration similar to: family ethernet-switching { filter L2-VLAN { term ALLOW { from { user-vlan-id 100; } then { accept; } } term NON-MATCH { then { discard; } } when there is only one term containing a 'user-vlan-id' match condition, and no other terms in the firewall filter except discard, the discard action for non-matching traffic will only discard traffic with the same VLAN ID specified under 'user-vlan-id'. Other traffic (e.g. VLAN ID 200) will not be discarded. This unexpected behavior can lead to unintended traffic passing through the interface where the firewall filter is applied. This issue only affects systems using VXLANs. This issue affects Juniper Networks Junos OS on QFX5K Series: 18.1 versions prior to 18.1R3-S7, except 18.1R3; 18.2 versions prior to 18.2R2-S7, 18.2R3-S1; 18.3 versions prior to 18.3R1-S5, 18.3R2-S4, 18.3R3; 18.4 versions prior to 18.4R1-S7, 18.4R2-S1, 18.4R3; 19.1 versions prior to 19.1R1-S5, 19.1R2; 19.2 versions prior to 19.2R1-S5, 19.2R2.
problem types: CWE-203 Information Exposure Through Discrepancy
affected:
{
platforms: EX4600, QFX5K Series
product: Junos OS
vendor: Juniper Networks
versions:
status: unaffected, version: 18.1R3
lessThan: 18.1R3-S7, status: affected, version: 18.1, versionType: custom
lessThan: 18.2R2-S7, 18.2R3-S1, status: affected, version: 18.2, versionType: custom
lessThan: 18.3R1-S5, 18.3R2-S4, 18.3R3, status: affected, version: 18.3, versionType: custom
lessThan: 18.4R1-S7, 18.4R2-S1, 18.4R3, status: affected, version: 18.4, versionType: custom
lessThan: 19.1R1-S5, 19.1R2, status: affected, version: 19.1, versionType: custom
lessThan: 19.2R1-S5, 19.2R2, status: affected, version: 19.2, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 5.8
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: LOW
privilegesRequired: NONE
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
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 18.1R3-S7, 18.2R2-S7, 18.2R3-S1, 18.3R1-S5, 18.3R2-S4, 18.3R3, 18.4R1-S7, 18.4R2-S1, 18.4R3, 19.1R1-S5, 19.1R2, 19.2R1-S5, 19.2R2, 19.3R1, and all subsequent releases.
workarounds: Avoid using the user-vlan-id match criteria.