CVE-2021-31377

Junos OS: A local authenticated attacker can cause RPD to core

Description

An Incorrect Permission Assignment for Critical Resource vulnerability of a certain file in the filesystem of Junos OS allows a local authenticated attacker to cause routing process daemon (RPD) to crash and restart, causing a Denial of Service (DoS). Repeated actions by the attacker will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R2-S13, 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S8, 18.4R3-S7; 19.1 versions prior to 19.1R2-S3, 19.1R3-S5; 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R1-S1, 20.4R2.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: 15.1R7-S9, 17.3R3-S12, 17.4R2-S13, 17.4R3-S5, 18.1R3-S13, 18.2R3-S8, 18.3R3-S5, 18.4R2-S8, 18.4R3-S7, 19.1R3-S5, 19.2R3-S2, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3-S2, 20.1R2-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R3, 20.4R1-S1, 20.4R2, 21.1R1, and all subsequent releases.

Workaround:

  • To reduce the risk of exploitation of this issue, use access lists or firewall filters to limit access to only trusted administrative networks, hosts and users.

Category

5.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.03%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11242 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-31377?
CVE-2021-31377 has been scored as a medium severity vulnerability.
How to fix CVE-2021-31377?
To fix CVE-2021-31377: The following software releases have been updated to resolve this specific issue: 15.1R7-S9, 17.3R3-S12, 17.4R2-S13, 17.4R3-S5, 18.1R3-S13, 18.2R3-S8, 18.3R3-S5, 18.4R2-S8, 18.4R3-S7, 19.1R3-S5, 19.2R3-S2, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3-S2, 20.1R2-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R3, 20.4R1-S1, 20.4R2, 21.1R1, and all subsequent releases.
Is CVE-2021-31377 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-31377 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-2021-31377?
CVE-2021-31377 affects Juniper Networks Junos OS.
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