Product Affected

This issue affects Junos OS 15.1, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4, 20.1, 20.2, 20.3, 20.4.
Medium
5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

Problem

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.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was found during internal product security testing or research.

This issue has been assigned CVE-2021-31377 .

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.

This issue is being tracked as 1543261 .

Software releases or updates are available for download at https://support.juniper.net/support/downloads/

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.

Severity Assessment

Information for how Juniper Networks uses CVSS can be found at KB 16446 [juniper.net] "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

Modification History

2021-10-13: Initial Publication.

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