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Product Affected

This issue affects all versions of Junos OS and Junos OS Evolved.

Severity

High

Severity Assessment (CVSS) Score

CVSS: v3.1: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVSS: v4.0: 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/R:A/RE:M)

Problem

An Improper Check for Unusual or Exceptional Conditions vulnerability in the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network based attacker to cause a Denial of Service (DoS).

In a scenario where BGP Monitoring Protocol (BMP) is configured with rib-in pre-policy monitoring, receiving a BGP update with a specifically malformed AS PATH attribute over an established BGP session, can cause an RPD crash and restart.

This issue affects:

Junos OS:

All versions before 21.2R3-S8,
21.4 versions before 21.4R3-S8,
22.2 versions before 22.2R3-S4,
22.3 versions before 22.3R3-S3,
22.4 versions before 22.4R3-S2,
23.2 versions before 23.2R2-S1,
23.4 versions before 23.4R1-S2, 23.4R2;

Junos OS Evolved:

All versions before 21.2R3-S8-EVO,
21.4 versions before 21.4R3-S8-EVO,
22.2 versions before 22.2R3-S4-EVO,
22.3 versions before 22.3R3-S3-EVO,
22.4 versions before 22.4R3-S2-EVO,
23.2 versions before 23.2R2-S1-EVO,
23.4 versions before 23.4R1-S2-EVO, 23.4R2-EVO.

To be exposed to this issue pre-policy for BMP needs to be configured at least once:

[ protocols bgp ... bmp route-monitoring pre-policy ]

[ routing-options bmp ... route-monitoring pre-policy ]

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

This issue was seen during production usage.

Solution

The following software releases have been updated to resolve this specific issue:
Junos OS Evolved: 21.2R3-S8-EVO, 21.4R3-S8-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-S2-EVO, 23.2R2-S1-EVO, 23.4R1-S2-EVO, 23.4R2-EVO, 24.2R1-EVO, and all subsequent releases;
Junos OS: 21.2R3-S8, 21.4R3-S8, 22.2R3-S4, 22.3R3-S3, 22.4R3-S2, 23.2R2-S1, 23.4R1-S2, 23.4R2, 24.2R1, and all subsequent releases.

This issue is being tracked as 1800905 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

As a work-around, the "exclude-non-feasible" knob can be configured to prevent the crash at:
[ protocols bgp ... bmp route-monitoring pre-policy exclude-non-feasible ]or[ routing-options bmp ... route-monitoring pre-policy exclude-non-feasible ]depending on where pre-policy is configured.

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