title: Junos OS: EX4300: Traffic from the network internal to the device (128.0.0.0) may be forwarded to egress interfaces
description: Juniper Networks Junos OS uses the 128.0.0.0/2 subnet for internal communications between the RE and PFEs. It was discovered that packets utilizing these IP addresses may egress an EX4300 switch, leaking configuration information such as heartbeats, kernel versions, etc. out to the Internet, leading to an information exposure vulnerability. This issue affects Juniper Networks Junos OS: 14.1X53 versions prior to 14.1X53-D53 on EX4300; 15.1 versions prior to 15.1R7-S6 on EX4300; 15.1X49 versions prior to 15.1X49-D200, 15.1X49-D210 on EX4300; 16.1 versions prior to 16.1R7-S7 on EX4300; 17.1 versions prior to 17.1R2-S11, 17.1R3-S2 on EX4300; 17.2 versions prior to 17.2R3-S3 on EX4300; 17.3 versions prior to 17.3R2-S5, 17.3R3-S7 on EX4300; 17.4 versions prior to 17.4R2-S9, 17.4R3 on EX4300; 18.1 versions prior to 18.1R3-S8 on EX4300; 18.2 versions prior to 18.2R3-S2 on EX4300; 18.3 versions prior to 18.3R2-S3, 18.3R3, 18.3R3-S1 on EX4300; 18.4 versions prior to 18.4R1-S5, 18.4R2-S3, 18.4R3 on EX4300; 19.1 versions prior to 19.1R1-S4, 19.1R2 on EX4300; 19.2 versions prior to 19.2R1-S4, 19.2R2 on EX4300; 19.3 versions prior to 19.3R1-S1, 19.3R2 on EX4300.
problem types: CWE-200 Information Exposure
affected:
{
platforms: EX4300
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 14.1X53-D53, status: affected, version: 14.1X53, versionType: custom
lessThan: 15.1R7-S6, status: affected, version: 15.1, versionType: custom
lessThan: 15.1X49-D200, 15.1X49-D210, status: affected, version: 15.1X49, versionType: custom
lessThan: 16.1R7-S7, status: affected, version: 16.1, versionType: custom
lessThan: 17.1R2-S11, 17.1R3-S2, status: affected, version: 17.1, versionType: custom
lessThan: 17.2R3-S3, status: affected, version: 17.2, versionType: custom
lessThan: 17.3R2-S5, 17.3R3-S7, status: affected, version: 17.3, versionType: custom
lessThan: 17.4R2-S9, 17.4R3, status: affected, version: 17.4, versionType: custom
lessThan: 18.1R3-S8, status: affected, version: 18.1, versionType: custom
lessThan: 18.2R3-S2, status: affected, version: 18.2, versionType: custom
lessThan: 18.3R2-S3, 18.3R3, 18.3R3-S1, status: affected, version: 18.3, versionType: custom
lessThan: 18.4R1-S5, 18.4R2-S3, 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-S4, 19.2R2, status: affected, version: 19.2, versionType: custom
lessThan: 19.3R1-S1, 19.3R2, status: affected, version: 19.3, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 5.3
baseSeverity: MEDIUM
confidentialityImpact: LOW
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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: 14.1X53-D53, 15.1R7-S6, 15.1X49-D200, 15.1X49-D210, 16.1R7-S7, 17.1R2-S11, 17.1R3-S2, 17.2R3-S3, 17.3R2-S5, 17.3R3-S7, 17.4R2-S9, 17.4R3, 18.1R3-S8, 18.2R3-S2, 18.3R2-S3, 18.3R3, 18.3R3-S1, 18.4R1-S5, 18.4R2-S3, 18.4R3, 19.1R1-S4, 19.1R2, 19.2R1-S4, 19.2R2, 19.3R1-S1, 19.3R2, 19.4R1, and all subsequent releases.
workarounds: Configure a firewall filter to discard packets sourced from the internal network.
Disabling the net.transit_re sysctl flag will also cause management traffic forwarded to the PFE ports to be dropped:
% sysctl -w net.transit_re=0
Note that sysctl flags do not survive a reboot.