Product Affected

This issue affects all versions of Junos OS Evolved.
Medium
CVSS 3.1: 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVSS 4.0: 8.2 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/R:A)

Problem

An Improper Check for Unusual or Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS Evolved may allow a network-based unauthenticated attacker to crash the device (vmcore) by sending a specific TCP packet over an established TCP session with MD5 authentication enabled, destined to an accessible port on the device, resulting in a Denial of Service (DoS).  The receipt of this packet must occur within a specific timing window outside the attacker's control (i.e., race condition).

Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.

This issue only affects dual RE systems with Nonstop Active Routing (NSR) enabled.
Exploitation can only occur over TCP sessions with MD5 authentication enabled (e.g., BGP with MD5 authentication).
 

This issue affects Junos OS Evolved: 

  • All versions before 21.2R3-S8-EVO,
  • from 21.4-EVO before 21.4R3-S6-EVO,
  • from 22.1-EVO before 22.1R3-S4-EVO,
  • from 22.2-EVO before 22.2R3-S4-EVO,
  • from 22.3-EVO before 22.3R3-S3-EVO,
  • from 22.4-EVO before 22.4R2-S2-EVO, 22.4R3-EVO.

An example of a system with NSR enabled is shown below:
[ routing-options nonstop-routing ]

MD5 authentication is enabled for BGP using the following configuration option:
[ protocols bgp ... authentication-key <password> ]
 

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

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

Solution

The following software releases have been updated to resolve this specific issue: 21.2R3-S8-EVO, 21.4R3-S6-EVO, 22.1R3-S4-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R2-S2-EVO, 22.4R3-EVO, 23.2R1-EVO, and all subsequent releases.
 

This issue is being tracked as 1723268 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.
 

However, the risk of malicious exploitation can be reduced by limiting the exploitable attack surface of critical infrastructure networking equipment. 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

2024-07-10: Initial Publication
2024-09-13: Minor formatting change to CVSS field

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