Product Affected

This issue affects all versions of Junos OS Evolved.
Medium
CVSS 3.1: 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
CVSS 4.0: 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Problem

An Improper Restriction of Excessive Authentication Attempts vulnerability in Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to cause a limited Denial of Service (DoS) to the management plane.

When an incoming connection was blocked because it exceeded the connections-per-second rate-limit, the system doesn't consider existing connections anymore for subsequent connection attempts so that the connection limit can be exceeded.
 

This issue affects Junos OS Evolved:

  • All versions before 21.4R3-S4-EVO,
  • 22.1-EVO versions before 22.1R3-S3-EVO,
  • 22.2-EVO versions before 22.2R3-S2-EVO, 
  • 22.3-EVO versions before 22.3R2-S1-EVO, 22.3R3-EVO.


In order to be impacted by this issue the system needs to be configured with a connection-limit and a rate-limit for at least one of the following protocols / services. This can either be done explicit as shown below, but please note that these options are also in effect by default.

  [system services ( finger | ftp | netconf | ssh | telnet | xnm-clear-text | xnm-ssl | rest control | tftp-server ) connection-limit <limit>]
  [system services ( finger | ftp | netconf | ssh | telnet | xnm-clear-text | xnm-ssl | rest control | tftp-server ) rate-limit <limit>]

Solution

The following software releases have been updated to resolve this specific issue:
Junos OS Evolved: 20.4R3-S9-EVO, 21.4R3-S4-EVO, 21.4R3-S6-EVO, 22.1R3-S3-EVO, 22.2R3-S2-EVO, 22.3R2-S1-EVO, 22.3R3-EVO, 22.4R1-S2-EVO, 22.4R2-EVO, 22.4R3-EVO, 23.2R1-EVO, 23.2R2-EVO, and all subsequent releases.

This issue is being tracked as 1709385 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

Workaround

There are no known workarounds for this issue.

To reduce the risk of exploitation use access lists or firewall filters to limit access to the device only from trusted, administrative networks or hosts.

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

2024-04-10 - Initial Publication
2024-09-13: Minor formatting change to CVSS field

Related Information