CVE-2021-0243

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.

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.

Un manejo inapropiado de Datos Inesperados en el firewall policer de Juniper Networks Junos OS, en los switches EX4300, permite que el tráfico coincidente exceda los límites establecidos de policer, posiblemente conllevando a una condición limitada de Denegación de Servicio (DoS).&#xa0;Cuando la acción de descarte de firewall policer presenta un fallo en un puerto de Capa 2, permitirá que pase el tráfico aunque exceda los límites establecidos de policer.&#xa0;El tráfico no será descartado y será reenviado aunque una acción de descarte policer sea configurada.&#xa0;Cuando ocurre el problema, el tráfico no se descarta como se desea, lo cual se puede observar comparando los bytes de entrada con los bytes de salida usando el siguiente comando: 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. Este problema solo afecta a la generación de polítcaIPv4.&#xa0;El tráfico IPv6 y las acciones de generación de política del firewall no está afectadas por este problema.&#xa0;Este problema afecta a Juniper Networks Junos OS en la Serie EX4300: todas las versiones anteriores a 17.3R3-S10;&#xa0;versiones 17.4 anteriores a 17.4R3-S3;&#xa0;versiones 18.1 anteriores a 18.1R3-S11;&#xa0;versiones 18.2 anteriores a 18.2R3-S6;&#xa0;versiones 18.3 anteriores a 18.3R3-S4;&#xa0;versiones 18.4 anteriores a 18.4R3-S6;&#xa0;versiones 19.1 anteriores a 19.1R3-S3;&#xa0;versiones 19.2 anteriores a 19.2R3-S1;&#xa0;versiones 19.3 anteriores a 19.3R3-S1;&#xa0;versiones 19.4 anteriores a 19.4R3;&#xa0;versiones 20.1 anteriores a 20.1R2;&#xa0;versiones 20.2 anteriores a 20.2R2