An Improper Handling of Exceptional Conditions vulnerability in AS PATH processing of Juniper Networks Junos OS and Junos OS Evolved allows an attacker to send a BGP update message with an AS PATH containing a large number of 4-byte ASes, leading to a Denial of Service (DoS). Continued receipt and processing of these BGP updates will create a sustained Denial of Service (DoS) condition.

This issue is hit when the router has Non-Stop Routing (NSR) enabled, has a non-4-byte-AS capable BGP neighbor, receives a BGP update message with a prefix that includes a long AS PATH containing large number of 4-byte ASes, and has to advertise the prefix towards the non-4-byte-AS capable BGP neighbor.

Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability.
This issue affects:

Juniper Networks Junos OS:



* All versions prior to 20.4R3-S8;
* 21.1 versions 21.1R1 and later;
* 21.2 versions prior to 21.2R3-S6;
* 21.3 versions prior to 21.3R3-S5;
* 21.4 versions prior to 21.4R3-S5;
* 22.1 versions prior to 22.1R3-S4;
* 22.2 versions prior to 22.2R3-S2;
* 22.3 versions prior to 22.3R2-S2, 22.3R3-S1;
* 22.4 versions prior to 22.4R2-S1, 22.4R3.




Juniper Networks Junos OS Evolved



* All versions prior to 20.4R3-S8-EVO;
* 21.1 versions 21.1R1-EVO and later;
* 21.2 versions prior to 21.2R3-S6-EVO;
* 21.3 versions prior to 21.3R3-S5-EVO;
* 21.4 versions prior to 21.4R3-S5-EVO;
* 22.1 versions prior to 22.1R3-S4-EVO;
* 22.2 versions prior to 22.2R3-S2-EVO;
* 22.3 versions prior to 22.3R2-S2-EVO, 22.3R3-S1-EVO;
* 22.4 versions prior to 22.4R2-S1-EVO, 22.4R3-EVO.






Advisories
Source ID Title
EUVD EUVD EUVD-2023-48545 An Improper Handling of Exceptional Conditions vulnerability in AS PATH processing of Juniper Networks Junos OS and Junos OS Evolved allows an attacker to send a BGP update message with an AS PATH containing a large number of 4-byte ASes, leading to a Denial of Service (DoS). Continued receipt and processing of these BGP updates will create a sustained Denial of Service (DoS) condition. This issue is hit when the router has Non-Stop Routing (NSR) enabled, has a non-4-byte-AS capable BGP neighbor, receives a BGP update message with a prefix that includes a long AS PATH containing large number of 4-byte ASes, and has to advertise the prefix towards the non-4-byte-AS capable BGP neighbor. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. This issue affects: Juniper Networks Junos OS: * All versions prior to 20.4R3-S8; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3-S1; * 22.4 versions prior to 22.4R2-S1, 22.4R3. Juniper Networks Junos OS Evolved * All versions prior to 20.4R3-S8-EVO; * 21.1 versions 21.1R1-EVO and later; * 21.2 versions prior to 21.2R3-S6-EVO; * 21.3 versions prior to 21.3R3-S5-EVO; * 21.4 versions prior to 21.4R3-S5-EVO; * 22.1 versions prior to 22.1R3-S4-EVO; * 22.2 versions prior to 22.2R3-S2-EVO; * 22.3 versions prior to 22.3R2-S2-EVO, 22.3R3-S1-EVO; * 22.4 versions prior to 22.4R2-S1-EVO, 22.4R3-EVO.
Fixes

Solution

The following software releases have been updated to resolve this specific issue: Junos OS: 20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S2, 22.3R2-S2, 22.3R3-S1, 22.4R2-S1, 22.4R3, 23.2R1, and all subsequent releases. Junos OS Evolved: 20.4R3-S8-EVO, 21.2R3-S6-EVO, 21.3R3-S5-EVO, 21.4R3-S5-EVO, 22.1R3-S4-EVO, 22.2R3-S2-EVO, 22.3R2-S2-EVO, 22.3R3-S1-EVO, 22.4R2-S1-EVO, 22.4R3-EVO, 23.2R1-EVO, and all subsequent releases.


Workaround

Current operational and security best practices, such as limiting the AS PATH length, should mitigate risk of this issue. Below is an example configuration to limit AS PATH to 30 entries: set groups BASE-POLICY policy-options policy-statement MaxAS-Limit-30 term more-than-30 from protocol bgp set groups BASE-POLICY policy-options policy-statement MaxAS-Limit-30 term more-than-30 from as-path 31as set groups BASE-POLICY policy-options policy-statement MaxAS-Limit-30 term more-than-30 then reject set groups BASE-POLICY policy-options policy-statement MaxAS-Limit-30 then accept set groups BASE-POLICY policy-options policy-statement Customer-IN term MaxAS-Limit from policy MaxAS-Limit-30 set groups BASE-BGP protocols bgp group <*-CUSTOMER> import Customer-IN set groups BASE-PREFIX-LISTS policy-options as-path 31as ".{31,}"

References
History

Tue, 03 Dec 2024 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: juniper

Published:

Updated: 2024-12-03T14:49:41.755Z

Reserved: 2023-09-26T19:30:27.953Z

Link: CVE-2023-44186

cve-icon Vulnrichment

Updated: 2024-08-02T19:59:51.607Z

cve-icon NVD

Status : Modified

Published: 2023-10-11T21:15:09.890

Modified: 2024-11-21T08:25:23.820

Link: CVE-2023-44186

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.