Junos OS and Junos OS Evolved: BGP session flaps on NSR-enabled devices can cause rpd crash
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, and 7 more
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Juniper Networks Junos OS
fixed in 20.4R3-S9; From 21.2 · fixed in 21.2R3-S7; From 21.3 · fixed in 21.3R3-S5; From 21.4 · fixed in 21.4R3-S5; From 22.1 · fixed in 22.1R3-S4; From 22.2 · fixed in 22.2R3-S3; From 22.3 · fixed in 22.3R3-S1
- Juniper Networks Junos OS Evolved
fixed in 21.3R3-S5-EVO; From 21.4 · fixed in 21.4R3-S5-EVO; From 22.1 · fixed in 22.1R3-S4-EVO; From 22.2 · fixed in 22.2R3-S3-EVO; From 22.3 · fixed in 22.3R3-S1-EVO