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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.3434 JSA11215 - 2021-10 Security Bulletin: Junos OS and Junos OS Evolved: Privilege escalation vulnerability in Juniper Extension Toolkit (JET) (CVE-2021-31350) 15 October 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Junos OS Junos OS Evolved Publisher: Juniper Networks Operating System: Juniper Impact/Access: Root Compromise -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2021-31350 Original Bulletin: http://kb.juniper.net/InfoCenter/index?page=content&id=JSA11215 - --------------------------BEGIN INCLUDED TEXT-------------------- 2021-10 Security Bulletin: Junos OS and Junos OS Evolved: Privilege escalation vulnerability in Juniper Extension Toolkit (JET) (CVE-2021-31350) Article ID : JSA11215 Last Updated: 13 Oct 2021 Version : 1.0 Product Affected: This issue affects Junos OS 18.4, 19.1, 19.2, 19.3, 19.4, 20.1, 20.2, 20.3, 20.4. This issue affects all versions of Junos OS Evolved. Problem: An Improper Privilege Management vulnerability in the gRPC framework, used by the Juniper Extension Toolkit (JET) API on Juniper Networks Junos OS and Junos OS Evolved, allows a network-based, low-privileged authenticated attacker to perform operations as root, leading to complete compromise of the targeted system. The issue is caused by the JET service daemon (jsd) process authenticating the user, then passing configuration operations directly to the management daemon (mgd) process, which runs as root. This issue affects Juniper Networks Junos OS: o 18.4 versions prior to 18.4R1-S8, 18.4R2-S8, 18.4R3-S8; o 19.1 versions prior to 19.1R2-S3, 19.1R3-S5; o 19.2 versions prior to 19.2R1-S7, 19.2R3-S2; o 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; o 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S3; o 20.1 versions prior to 20.1R2-S2, 20.1R3; o 20.2 versions prior to 20.2R2-S3, 20.2R3; o 20.3 versions prior to 20.3R2-S1, 20.3R3; o 20.4 versions prior to 20.4R2. This issue does not affect Juniper Networks Junos OS versions prior to 18.4R1. Juniper Networks Junos OS Evolved: o All versions prior to 20.4R2-EVO; o 21.1-EVO versions prior to 21.1R2-EVO. The following is an example of enabling gRPC in Junos: set system services extension-service request-response grpc ssl Juniper SIRT is not aware of any malicious exploitation of this vulnerability. This issue was found during internal product security testing or research. This issue has been assigned CVE-2021-31350 . Solution: The following software releases have been updated to resolve this specific issue: Junos OS 18.4R1-S8, 18.4R2-S8, 18.4R3-S8, 19.1R2-S3, 19.1R3-S5, 19.2R1-S7, 19.2R3-S2, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2-S1, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases. Junos OS Evolved 20.4R2-EVO, 21.1R2-EVO, 21.2R1-EVO, and all subsequent releases. This issue is being tracked as 1578302 . Workaround: Use access lists or firewall filters to limit access to the device via gRPC only from trusted hosts and from trusted administrators Implementation: Software releases or updates are available for download at https:// support.juniper.net/support/downloads/ Modification History: 2021-10-13: Initial Publication. CVSS Score: 7.5 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H) Severity Level: High Severity Assessment: Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories." - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. 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Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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