Product Affected

This issue affects Junos OS 17.3 and later versions prior to 18.3R3-S6, 18.4, 19.1, 19.2, 19.3, 19.4, 20.1, 20.2, 20.3, 20.4, 21.1, 21.2. Affected platforms: SRX Series.
High
7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Problem

A vulnerability in Juniper Networks Junos OS on SRX Series, allows a network-based unauthenticated attacker to cause a Denial of Service (DoS) by sending a specific fragmented packet to the device, resulting in a flowd process crash, which is responsible for packet forwarding.

Continued receipt and processing of this specific packet will create a sustained DoS condition.
 

This issue only affects SRX Series when 'preserve-incoming-fragment-size' feature is enabled.

This issue affects Juniper Networks Junos OS on SRX Series:

  • 18.3 versions prior to 18.3R3-S6;
  • 18.4 versions prior to 18.4R3-S10;
  • 19.1 versions prior to 19.1R3-S7;
  • 19.2 versions prior to 19.2R3-S4;
  • 19.3 versions prior to 19.3R3-S4;
  • 19.4 versions prior to 19.4R3-S6;
  • 20.1 versions prior to 20.1R3-S2;
  • 20.2 versions prior to 20.2R3-S3;
  • 20.3 versions prior to 20.3R3-S1;
  • 20.4 versions prior to 20.4R3;
  • 21.1 versions prior to 21.1R2-S1, 21.1R3;
  • 21.2 versions prior to 21.2R2.

This issue does not affect Juniper Networks Junos OS prior to 17.3R1.
 

The config stanza affected by this issue:

[ security flow preserve-incoming-fragment-size ]
 

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


This issue was seen during production usage.


This issue has been assigned CVE-2022-22185.

Solution

The following software releases have been updated to resolve this specific issue: 18.3R3-S6, 18.4R3-S10, 19.1R3-S7, 19.2R3-S4, 19.3R3-S4, 19.4R3-S6, 20.1R3-S2, 20.2R3-S3, 20.3R3-S1, 20.4R3, 21.1R2-S1, 21.1R3, 21.2R2, 21.3R1, and all subsequent releases.
 

This issue is being tracked as PR 1607782  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).

Implementation

Software Releases, patches and updates are available at https://support.juniper.net/support/downloads/.

Workaround

An administrator can disable the feature preserve-incoming-fragment-size to avoid this issue:

user@host# delete security flow preserve-incoming-fragment-size
user@host# commit

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

  • 2022-04-13: Initial Publication.

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