Improper Handling of Unexpected Data in the firewall policer of Juniper Networks Junos OS on EX4300 switches allows matching traffic to exceed set policer limits, possibly leading to a limited Denial of Service (DoS) condition. When the firewall policer discard action fails on a Layer 2 port, it will allow traffic to pass even though it exceeds set policer limits. Traffic will not get discarded, and will be forwarded even though a policer discard action is configured. When the issue occurs, traffic is not discarded as desired, which can be observed by comparing the Input bytes with the Output bytes using the following command: user@junos> monitor interface traffic Interface Link Input bytes (bps) Output bytes (bps) ge-0/0/0 Up 37425422 (82616) 37425354 (82616) <<<< egress ge-0/0/1 Up 37425898 (82616) 37425354 (82616) <<<< ingress The expected output, with input and output counters differing, is shown below: Interface Link Input bytes (bps) Output bytes (bps) ge-0/0/0 Up 342420570 (54600) 342422760 (54600) <<<< egress ge-0/0/1 Up 517672120 (84000) 342420570 (54600) <<<< ingress This issue only affects IPv4 policing. IPv6 traffic and firewall policing actions are not affected by this issue. This issue affects Juniper Networks Junos OS on the EX4300: All versions prior to 17.3R3-S10; 17.4 versions prior to 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R3-S6; 19.1 versions prior to 19.1R3-S3; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R3-S1; 19.4 versions prior to 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2.
Metrics
No CVSS v4.0
Attack Vector Adjacent Network
Attack Complexity Low
Privileges Required None
Scope Changed
Confidentiality Impact None
Integrity Impact None
Availability Impact Low
User Interaction None
No CVSS v3.0
Access Vector Adjacent Network
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact None
Availability Impact Partial
AV:A/AC:L/Au:N/C:N/I:N/A:P
This CVE is not in the KEV list.
Key SSVC decision points have not yet been added.
Affected Vendors & Products
Vendors | Products |
---|---|
Juniper |
|
Configuration 1 [-]
AND |
|
No data.
References
Link | Providers |
---|---|
https://kb.juniper.net/JSA11136 |
History
No history.
MITRE
Status: PUBLISHED
Assigner: juniper
Published: 2021-04-22T19:37:08.073257Z
Updated: 2024-09-17T00:51:52.928Z
Reserved: 2020-10-27T00:00:00
Link: CVE-2021-0243
Vulnrichment
No data.
NVD
Status : Analyzed
Published: 2021-04-22T20:15:09.093
Modified: 2021-04-27T17:11:41.870
Link: CVE-2021-0243
Redhat
No data.