Junos OS: Improper Handling of Exceptional Conditions
CVE-2023-44186 is a high-severity improper handling of exceptional conditions vulnerability in Junos OS from Juniper Networks, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 20.4R3-S8, 21.1*, 21.2R3-S6 as the first without the flaw, so updating Junos OS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Junos OS to 20.4R3-S8 or 21.1* or 21.2R3-S6 or 21.3R3-S5, whichever matches your release line, or a later version.
- Update Junos OS Evolved to 20.4R3-S8-EVO or 21.1*-EVO or 21.2R3-S6-EVO or 21.3R3-S5-EVO, whichever matches your release line, or a later version.
- Update Junos to 20.4 or a later version.
- Read the advisory on supportportal.juniper.net for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Juniper Networks | Junos OS | before 20.4R3-S8; 21.1R1 up to, but not including, 21.1*; 21.2 up to, but not including, 21.2R3-S6; 21.3 up to, but not including, 21.3R3-S5; 21.4 up to, but not including, 21.4R3-S5; 22.1 up to, but not including, 22.1R3-S4; 22.2 up to, but not including, 22.2R3-S2; 22.3 up to, but not including, 22.3R2-S2, 22.3R3-S1; and 1 more ranges | 20.4R3-S8, 21.1*, 21.2R3-S6, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4 |
| Juniper Networks | Junos OS Evolved | before 20.4R3-S8-EVO; 21.1 up to, but not including, 21.1*-EVO; 21.2 up to, but not including, 21.2R3-S6-EVO; 21.3 up to, but not including, 21.3R3-S5-EVO; 21.4 up to, but not including, 21.4R3-S5-EVO; 22.1 up to, but not including, 22.1R3-S4-EVO; 22.2 up to, but not including, 22.2R3-S2-EVO; 22.3 up to, but not including, 22.3R2-S2-EVO, 22.3R3-S1-EVO; and 1 more ranges | 20.4R3-S8-EVO, 21.1*-EVO, 21.2R3-S6-EVO, 21.3R3-S5-EVO, 21.4R3-S5-EVO, 22.1R3-S4-EVO |
| Juniper Networks | Junos | before 20.4; 20.4; 21.1; 21.2; 21.3; 21.4; 22.1; 22.2; and 4 more ranges | 20.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (juniper.net) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
An Improper Handling of Exceptional Conditions vulnerability in AS PATH processing of Juniper Networks Junos OS and Junos OS Evolved allows an attacker to send a BGP update message with an AS PATH containing a large number of 4-byte ASes, leading to a Denial of Service (DoS). Continued receipt and processing of these BGP updates will create a sustained Denial of Service (DoS) condition. This issue is hit when the router has Non-Stop Routing (NSR) enabled, has a non-4-byte-AS capable BGP neighbor, receives a BGP update message with a prefix that includes a long AS PATH containing large number of 4-byte ASes, and has to advertise the prefix towards the non-4-byte-AS capable BGP neighbor. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. This issue affects: Juniper Networks Junos OS: * All versions prior to 20.4R3-S8; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3-S1; * 22.4 versions prior to 22.4R2-S1, 22.4R3. Juniper Networks Junos OS Evolved * All versions prior to 20.4R3-S8-EVO; * 21.1 versions 21.1R1-EVO and later; * 21.2 versions prior to 21.2R3-S6-EVO; * 21.3 versions prior to 21.3R3-S5-EVO; * 21.4 versions prior to 21.4R3-S5-EVO; * 22.1 versions prior to 22.1R3-S4-EVO; * 22.2 versions prior to 22.2R3-S2-EVO; * 22.3 versions prior to 22.3R2-S2-EVO, 22.3R3-S1-EVO; * 22.4 versions prior to 22.4R2-S1-EVO, 22.4R3-EVO.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Handling of Exceptional Conditions
The product does not handle or incorrectly handles an exceptional condition.
More Improper Handling of Exceptional Conditions vulnerabilities (CWE-755)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- supportportal.juniper.net/JSA73150Mitigation
Other vulnerabilities in Junos OS
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
Recent Improper Handling of Exceptional Conditions vulnerabilities
- 7.5 High severity
- 8.6 High severity
- 7.5 High severity
- 8.4 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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