CVE-2021-31353

Summary

An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an attacker to inject a specific BGP update, causing the routing protocol daemon (RPD) to crash and restart, leading to a Denial of Service (DoS). Continued receipt and processing of the BGP update will create a sustained Denial of Service (DoS) condition. This issue affects very specific versions of Juniper Networks Junos OS: 19.3R3-S2; 19.4R3-S3; 20.2 versions 20.2R2-S3 and later, prior to 20.2R3-S2; 20.3 versions 20.3R2 and later, prior to 20.3R3; 20.4 versions 20.4R2 and later, prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS 20.1 is not affected by this issue. This issue also affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S3-EVO, 20.4R3-EVO; 21.1-EVO versions prior to 21.1R2-EVO; 21.2-EVO versions prior to 21.2R2-EVO.

Affected Software

VendorProductVersion RangeStatus
Juniper NetworksJunos OSunspecified < 19.3R3-S2unaffected
Juniper NetworksJunos OS19.3R3-S2affected
Juniper NetworksJunos OS19.4R3-S3affected
Juniper NetworksJunos OS20.1R1 < 20.1*unaffected
Juniper NetworksJunos OS20.2 < 20.2R2-S3unaffected
Juniper NetworksJunos OS20.3 < 20.3R2unaffected
Juniper NetworksJunos OS20.4 < 20.4R2unaffected
Juniper NetworksJunos OS21.1 < 21.1R2affected
Juniper NetworksJunos OS Evolvedunspecified < 20.4R2-S3-EVO, 20.4R3-EVOaffected
Juniper NetworksJunos OS Evolved21.1-EVO < 21.1R2-EVOaffected
Juniper NetworksJunos OS Evolved21.2-EVO < 21.2R2-EVOaffected

Weaknesses

  • CWE-755: CWE-755 Improper Handling of Exceptional Conditions

Workarounds

This issue can be mitigated in two ways:

  1. ensure that TTL propagation is either enabled or disabled in both places below: protocols mpls no-propagate-ttl routing-instance <vrf> no-vrf-propagate-ttl

  2. Disable multipath: routing-instance <vrf> routing-options multipath

ADP Enrichment

CVE Program Container

Additional References

References