CVE-2024-21585

MEDIUM
2024-01-12 [email protected]
5.9
CVSS 3.1
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CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

2
Analysis Generated
Mar 28, 2026 - 19:34 vuln.today
CVE Published
Jan 12, 2024 - 01:15 nvd
MEDIUM 5.9

Tags

Denial Of Service Juniper Junos Junos Os Evolved

Description

An Improper Handling of Exceptional Conditions vulnerability in BGP session processing of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network-based attacker, using specific timing outside the attacker's control, to flap BGP sessions and cause the routing protocol daemon (rpd) process to crash and restart, leading to a Denial of Service (DoS) condition. Continued BGP session flapping will create a sustained Denial of Service (DoS) condition. This issue only affects routers configured with non-stop routing (NSR) enabled. Graceful Restart (GR) helper mode, enabled by default, is also required for this issue to be exploitable. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. When the BGP session flaps on the NSR-enabled router, the device enters GR-helper/LLGR-helper mode due to the peer having negotiated GR/LLGR-restarter capability and the backup BGP requests for replication of the GR/LLGR-helper session, master BGP schedules, and initiates replication of GR/LLGR stale routes to the backup BGP. In this state, if the BGP session with the BGP peer comes up again, unsolicited replication is initiated for the peer without cleaning up the ongoing GR/LLGR-helper mode replication. This parallel two instances of replication for the same peer leads to the assert if the BGP session flaps again. This issue affects: Juniper Networks Junos OS * All versions earlier than 20.4R3-S9; * 21.2 versions earlier than 21.2R3-S7; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S4; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3; * 23.2 versions earlier than 23.2R1-S1, 23.2R2. Juniper Networks Junos OS Evolved * All versions earlier than 21.3R3-S5-EVO; * 21.4 versions earlier than 21.4R3-S5-EVO; * 22.1 versions earlier than 22.1R3-S4-EVO; * 22.2 versions earlier than 22.2R3-S3-EVO; * 22.3 versions earlier than 22.3R3-S1-EVO; * 22.4 versions earlier than 22.4R2-S2-EVO, 22.4R3-EVO; * 23.2 versions earlier than 23.2R1-S1-EVO, 23.2R2-EVO.

Analysis

An Improper Handling of Exceptional Conditions vulnerability in BGP session processing of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network-based attacker, using. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.

Technical Context

This vulnerability is classified under CWE-755. An Improper Handling of Exceptional Conditions vulnerability in BGP session processing of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network-based attacker, using specific timing outside the attacker's control, to flap BGP sessions and cause the routing protocol daemon (rpd) process to crash and restart, leading to a Denial of Service (DoS) condition. Continued BGP session flapping will create a sustained Denial of Service (DoS) condition. This issue only affects routers configured with non-stop routing (NSR) enabled. Graceful Restart (GR) helper mode, enabled by default, is also required for this issue to be exploitable. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. When the BGP session flaps on the NSR-enabled router, the device enters GR-helper/LLGR-helper mode due to the peer having negotiated GR/LLGR-restarter capability and the backup BGP requests for replication of the GR/LLGR-helper session, master BGP schedules, and initiates replication of GR/LLGR stale routes to the backup BGP. In this state, if the BGP session with the BGP peer comes up again, unsolicited replication is initiated for the peer without cleaning up the ongoing GR/LLGR-helper mode replication. This parallel two instances of replication for the same peer leads to the assert if the BGP session flaps again. This issue affects: Juniper Networks Junos OS * All versions earlier than 20.4R3-S9; * 21.2 versions earlier than 21.2R3-S7; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S4; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3; * 23.2 versions earlier than 23.2R1-S1, 23.2R2. Juniper Networks Junos OS Evolved * All versions earlier than 21.3R3-S5-EVO; * 21.4 versions earlier than 21.4R3-S5-EVO; * 22.1 versions earlier than 22.1R3-S4-EVO; * 22.2 versions earlier than 22.2R3-S3-EVO; * 22.3 versions earlier than 22.3R3-S1-EVO; * 22.4 versions earlier than 22.4R2-S2-EVO, 22.4R3-EVO; * 23.2 versions earlier than 23.2R1-S1-EVO, 23.2R2-EVO. Affected products include: Juniper Junos, Juniper Junos Os Evolved.

Affected Products

Juniper Junos, Juniper Junos Os Evolved.

Remediation

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Priority Score

30
Low Medium High Critical
KEV: 0
EPSS: +0.1
CVSS: +30
POC: 0

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CVE-2024-21585 vulnerability details – vuln.today
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