PT-2021-3665 · Juniper Networks · Junos

Published 2021-07-14 · Updated 2021-07-28 · CVE-2021-0289

Positive Technologies (AI Summary)

CVSS v3.1

6.5

Medium

Base vector

AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Juniper Networks Junos OS versions 5.6R1 through 18.4R2-S8 Juniper Networks Junos OS versions 18.4R3 through 18.4R3-S8 Juniper Networks Junos OS versions 19.4 through 19.4R3-S2 Juniper Networks Junos OS versions 20.1 through 20.1R2 Juniper Networks Junos OS versions 20.2 through 20.2R3-S1 Juniper Networks Junos OS versions 20.3 through 20.3R2 Juniper Networks Junos OS versions 20.4 through 20.4R2 Juniper Networks Junos OS versions 21.1 through 21.1R1 Juniper Networks Junos OS version 15.1 through 15.1R7-S9 Juniper Networks Junos OS version 20.3R1

Description A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability exists between the Device Control Daemon (DCD) and firewall process (dfwd) daemons of Juniper Networks Junos OS. This vulnerability allows an attacker to bypass the user-defined ARP Policer when it is configured and applied on one or more Aggregated Ethernet (AE) interface units. The user-defined ARP Policer is replaced with the default ARP Policer. To verify the desired ARP Policers and actual state, one can run the command "show interfaces <> extensive" and review the output.

Recommendations For Juniper Networks Junos OS versions 5.6R1 through 18.4R2-S8, update to version 18.4R2-S9 or later. For Juniper Networks Junos OS versions 18.4R3 through 18.4R3-S8, update to version 18.4R3-S9 or later. For Juniper Networks Junos OS versions 19.4 through 19.4R3-S2, update to version 19.4R3-S3 or later. For Juniper Networks Junos OS versions 20.1 through 20.1R2, update to version 20.1R3 or later. For Juniper Networks Junos OS versions 20.2 through 20.2R3-S1, update to version 20.2R3-S2 or later. For Juniper Networks Junos OS versions 20.3 through 20.3R2, update to version 20.3R2 or later. For Juniper Networks Junos OS versions 20.4 through 20.4R2, update to version 20.4R3 or later. For Juniper Networks Junos OS versions 21.1 through 21.1R1, update to version 21.1R2 or later. For Juniper Networks Junos OS version 15.1 through 15.1R7-S9, update to version 15.1R7-S10 or later. For Juniper Networks Junos OS version 20.3R1, update to version 20.3R2 or later.

Fix

Time Of Check To Time Of Use

Weakness Enumeration

CWE-367

Related Identifiers

BDU:2021-03898

CVE-2021-0289

Affected Products

Junos

References · 4

• https://bdu.fstec.ru/vul/2021-03898 · Security Note
• https://kb.juniper.net/JSA11191 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-0289 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-0289 · Security Note