CVE-2021-31362

Junos OS and Junos OS Evolved: An IS-IS adjacency might be taken down if a bad hello PDU is received for an existing adjacency causing a DoS

Description

A Protection Mechanism Failure vulnerability in RPD (routing protocol daemon) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent unauthenticated attacker to cause established IS-IS adjacencies to go down by sending a spoofed hello PDU leading to a Denial of Service (DoS) condition. Continued receipted of these spoofed PDUs will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS All versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R3-S3; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R3; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2. Juniper Networks Junos OS Evolved All versions prior to 20.4R2-EVO; 21.1 versions prior to 21.1R2-EVO.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue in JUNOS OS: 18.2R3-S8, 18.3R3-S5, 18.4R3-S9, 19.1R3-S7, 19.2R1-S7, 19.2R3-S3, 19.3R2-S6, 19.3R3-S2, 19.4R3-S3, 20.1R3, 20.2R3, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases. The following software releases have been updated to resolve this specific issue in JUNOS OS Evolved: 20.4R2-EVO, 21.1R2-EVO, 21.2R1-EVO, and all subsequent releases.

Workaround:

  • There are no viable workarounds for this issue.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.08%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Affected: Juniper Networks Junos OS Evolved
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11224 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-31362?
CVE-2021-31362 has been scored as a medium severity vulnerability.
How to fix CVE-2021-31362?
To fix CVE-2021-31362: The following software releases have been updated to resolve this specific issue in JUNOS OS: 18.2R3-S8, 18.3R3-S5, 18.4R3-S9, 19.1R3-S7, 19.2R1-S7, 19.2R3-S3, 19.3R2-S6, 19.3R3-S2, 19.4R3-S3, 20.1R3, 20.2R3, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases. The following software releases have been updated to resolve this specific issue in JUNOS OS Evolved: 20.4R2-EVO, 21.1R2-EVO, 21.2R1-EVO, and all subsequent releases.
Is CVE-2021-31362 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-31362 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-31362?
CVE-2021-31362 affects Juniper Networks Junos OS, Juniper Networks Junos OS Evolved.
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