Loading HuntDB...
Hunt
Vulnerability Intelligence by wss.sh
Home Daily Briefings High Impact CVEs Recent Exploits KEV Catalog GitHub Advisories Latest Updates Security News
Sign In Sign Up

CVE-2021-0289

MEDIUM
Published 2021-07-15T20:01:05.615580Z
Actions:

Expert Analysis

Professional remediation guidance

Get tailored security recommendations from our analyst team for CVE-2021-0289. We'll provide specific mitigation strategies based on your environment and risk profile.

CVSS Score

V3.1
6.5
/10
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score Metrics
Exploitability: N/A Impact: N/A

EPSS Score

v2025.03.14
0.001
probability
of exploitation in the wild

There is a 0.1% chance that this vulnerability will be exploited in the wild within the next 30 days.

Updated: 2025-06-25
Exploit Probability
Percentile: 0.198
Higher than 19.8% of all CVEs

Attack Vector Metrics

Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED

Impact Metrics

Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Description

When user-defined ARP Policer is configured and applied on one or more Aggregated Ethernet (AE) interface units, a Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability between the Device Control Daemon (DCD) and firewall process (dfwd) daemons of Juniper Networks Junos OS allows an attacker to bypass the user-defined ARP Policer. In this particular case the User ARP policer is replaced with default ARP policer. To review the desired ARP Policers and actual state one can run the command "show interfaces <> extensive" and review the output. See further details below. An example output is: show interfaces extensive | match policer Policer: Input: __default_arp_policer__ <<< incorrect if user ARP Policer was applied on an AE interface and the default ARP Policer is displayed Policer: Input: jtac-arp-ae5.317-inet-arp <<< correct if user ARP Policer was applied on an AE interface For all platforms, except SRX Series: This issue affects Juniper Networks Junos OS: All versions 5.6R1 and all later versions prior to 18.4 versions prior to 18.4R2-S9, 18.4R3-S9 with the exception of 15.1 versions 15.1R7-S10 and later versions; 19.4 versions prior to 19.4R3-S3; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R3-S2; 20.3 version 20.3R1 and later versions; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2; This issue does not affect Juniper Networks Junos OS versions prior to 5.6R1. On SRX Series this issue affects Juniper Networks Junos OS: 18.4 versions prior to 18.4R2-S9, 18.4R3-S9; 19.4 versions prior to 19.4R3-S4; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R3-S2; 20.3 version 20.3R1 and later versions; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2. This issue does not affect 18.4 versions prior to 18.4R1 on SRX Series. This issue does not affect Junos OS Evolved.

Available Exploits

No exploits available for this CVE.

Related News

No news articles found for this CVE.

Affected Products

Juniper Networks

Junos OS

Affected Versions:

unspecified 5.6R1 15.1 16.1R1 16.2R1 17.1R1 17.2R1 17.3R1 17.4R1 18.1R1 18.2R1 18.3R1 18.4 19.4 20.1 20.2 20.3R1 20.4 21.1
Juniper Networks

Junos OS

Affected Versions:

18.4 19.4 20.1 20.2 20.3R1 20.4 21.1
Juniper Networks

Junos OS Evolved

Affected Versions:

Any

GitHub Security Advisories

Community-driven vulnerability intelligence from GitHub

⚠ Unreviewed MODERATE

GHSA-2xhh-mjxg-mxhc

Advisory Details

When user-defined ARP Policer is configured and applied on one or more Aggregated Ethernet (AE) interface units, a Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability between the Device Control Daemon (DCD) and firewall process (dfwd) daemons of Juniper Networks Junos OS allows an attacker to bypass the user-defined ARP Policer. In this particular case the User ARP policer is replaced with default ARP policer. To review the desired ARP Policers and actual state one can run the command "show interfaces <> extensive" and review the output. See further details below. An example output is: show interfaces extensive | match policer Policer: Input: __default_arp_policer__ <<< incorrect if user ARP Policer was applied on an AE interface and the default ARP Policer is displayed Policer: Input: jtac-arp-ae5.317-inet-arp <<< correct if user ARP Policer was applied on an AE interface For all platforms, except SRX Series: This issue affects Juniper Networks Junos OS: All versions 5.6R1 and all later versions prior to 18.4 versions prior to 18.4R2-S9, 18.4R3-S9 with the exception of 15.1 versions 15.1R7-S10 and later versions; 19.4 versions prior to 19.4R3-S3; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R3-S2; 20.3 version 20.3R1 and later versions; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2; This issue does not affect Juniper Networks Junos OS versions prior to 5.6R1. On SRX Series this issue affects Juniper Networks Junos OS: 18.4 versions prior to 18.4R2-S9, 18.4R3-S9; 19.4 versions prior to 19.4R3-S4; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R3-S2; 20.3 version 20.3R1 and later versions; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2. This issue does not affect 18.4 versions prior to 18.4R1 on SRX Series. This issue does not affect Junos OS Evolved.

CVSS Scoring

CVSS Score

5.0

References

ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2021-0289
WEB https://kb.juniper.net/JSA11191

Advisory provided by GitHub Security Advisory Database. Published: May 24, 2022, Modified: May 24, 2022

References

https://kb.juniper.net/JSA11191
Published: 2021-07-15T20:01:05.615580Z
Last Modified: 2024-09-17T03:48:59.800Z
Copied to clipboard!