CVE-2021-0247 Information

Description

A Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization) vulnerability in the firewall process (dfwd) of Juniper Networks Junos OS allows an attacker to bypass the firewall rule sets applied to the input loopback filter on any interfaces of a device. This issue is detectable by reviewing the PFE firewall rules as well as the firewall counters and seeing if they are incrementing or not. For example: show firewall Filter: default_bpdu_filter Filter: FILTER-INET-01 Counters: Name Bytes Packets output-match-inet 0 0 ««« missing firewall packet count This issue affects: Juniper Networks Junos OS 14.1X53 versions prior to 14.1X53-D53 on QFX Series; 14.1 versions 14.1R1 and later versions prior to 15.1 versions prior to 15.1R7-S6 on QFX Series PTX Series; 15.1X53 versions prior to 15.1X53-D593 on QFX Series; 16.1 versions prior to 16.1R7-S7 on QFX Series PTX Series; 16.2 versions prior to 16.2R2-S11 16.2R3 on QFX Series PTX Series; 17.1 versions prior to 17.1R2-S11 17.1R3-S2 on QFX Series PTX Series; 17.2 versions prior to 17.2R1-S9 17.2R3-S3 on QFX Series PTX Series; 17.3 versions prior to 17.3R2-S5 17.3R3-S7 on QFX Series PTX Series; 17.4 versions prior to 17.4R2-S9 17.4R3 on QFX Series PTX Series; 18.1 versions prior to 18.1R3-S9 on QFX Series PTX Series; 18.2 versions prior to 18.2R2-S6 18.2R3-S3 on QFX Series PTX Series; 18.3 versions prior to 18.3R1-S7 18.3R2-S3 18.3R3-S1 on QFX Series PTX Series; 18.4 versions prior to 18.4R1-S5 18.4R2-S3 18.4R2-S7 18.4R3 on QFX Series PTX Series; 19.1 versions prior to 19.1R1-S4 19.1R2-S1 19.1R3 on QFX Series PTX Series; 19.2 versions prior to 19.2R1-S3 19.2R2 on QFX Series PTX Series.

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:L

Reference

https://kb.juniper.net/JSA11140

Attack Complexity

HIGH

Privileges Required

HIGH

User Interaction Required

HIGH

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

LOW

Availability Impact

LOW

Base Score

LOW

Base Severity

5.5