CVE-2021-31353: Junos OS and Junos OS Evolved: RPD core upon receipt of specific BGP update
First published: Tue Oct 19 2021(Updated: )
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.
Credit: sirt@juniper.net
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Juniper JUNOS | =19.3-r3-s2 | |
| Juniper JUNOS | =19.4-r3-s3 | |
| Juniper JUNOS | =20.2-r2-s3 | |
| Juniper JUNOS | =20.2-r3 | |
| Juniper JUNOS | =20.2-r3-s1 | |
| Juniper JUNOS | =20.3-r2 | |
| Juniper JUNOS | =20.3-r2-s1 | |
| Juniper JUNOS | =20.4-r2 | |
| Juniper JUNOS | =20.4-r2-s1 | |
| Juniper JUNOS | =21.1-r1 | |
| Juniper JUNOS | =21.1-r1-s1 | |
| Juniper Junos Os Evolved | <=20.3 | |
| Juniper Junos Os Evolved | =20.4-r1 | |
| Juniper Junos Os Evolved | =20.4-r1-s1 | |
| Juniper Junos Os Evolved | =20.4-r1-s2 | |
| Juniper Junos Os Evolved | =20.4-r2 | |
| Juniper Junos Os Evolved | =20.4-r2-s1 | |
| Juniper Junos Os Evolved | =20.4-r2-s2 | |
| Juniper Junos Os Evolved | =21.1-r1 | |
| Juniper Junos Os Evolved | =21.1-r1-s1 | |
| Juniper Junos Os Evolved | =21.2-r1 | |
| Juniper Junos Os Evolved | =21.2-r1-s1 |
Remedy
The following software releases have been updated to resolve this specific issue: Junos OS 18.4R2-S9, 19.1R3-S7, 19.3R3-S3, 19.4R1-S4, 19.4R3-S4, 20.1R3, 20.2R3-S2, 20.3R3, 20.4R3, 21.1R2, 21.2R1, 21.2R2, 21.3R1, and all subsequent releases. Junos OS Evolved 20.4R2-S3-EVO, 20.4R3-EVO, 21.1R2-EVO, 21.2R2-EVO, 21.3R1-EVO, and all subsequent releases. Note: Only those releases listed in the PROBLEM section above are affected. This fix has also been proactively committed into other releases that are not vulnerable to this issue.
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Reference Links
Frequently Asked Questions
What is CVE-2021-31353?
CVE-2021-31353 is an Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved.
How does CVE-2021-31353 impact Juniper Networks Junos OS?
CVE-2021-31353 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) impact.
What is the severity of CVE-2021-31353?
CVE-2021-31353 has a severity rating of 7.5 (High).
Which versions of Juniper Networks Junos OS are affected by CVE-2021-31353?
CVE-2021-31353 affects Juniper Networks Junos OS versions 19.3-r3-s2, 19.4-r3-s3, 20.2-r2-s3, 20.2-r3, 20.2-r3-s1, 20.3-r2, 20.3-r2-s1, 20.4-r2, 20.4-r2-s1, 21.1-r1, and 21.1-r1-s1.
How do I fix the CVE-2021-31353 vulnerability in Juniper Networks Junos OS?
To fix the CVE-2021-31353 vulnerability, it is recommended to upgrade to a fixed version of Juniper Networks Junos OS.
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- vendor/juniper
- canonical/juniper junos
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- version/juniper junos/19.4-r3-s3
- version/juniper junos/20.2-r2-s3
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- version/juniper junos/20.2-r3-s1
- version/juniper junos/20.3-r2
- version/juniper junos/20.3-r2-s1
- version/juniper junos/20.4-r2
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- version/juniper junos/21.1-r1
- version/juniper junos/21.1-r1-s1
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- version/juniper junos os evolved/21.2-r1
- version/juniper junos os evolved/21.2-r1-s1