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2020-10 Security Bulletin: Junos OS: MX series/EX9200 Series: IPv6 DDoS protection does not work as expected. (CVE-2020-1665)



Article ID: JSA11062 SECURITY_ADVISORIES Last Updated: 15 Jun 2021Version: 4.0
Product Affected:
This issue affects Junos OS 17.2, 17.2X75, 17.3, 17.4, 18.2, 18.2X75, 18.3. Affected platforms: MX series/EX9200 Series.

On Juniper Networks MX Series and EX9200 Series, in a certain condition the IPv6 Distributed Denial of Service (DDoS) protection might not take affect when it reaches the threshold condition.

The DDoS protection allows the device to continue to function while it is under DDoS attack, protecting both the Routing Engine (RE) and the Flexible PIC Concentrator (FPC) during the DDoS attack.

When this issue occurs, the RE and/or the FPC can become overwhelmed, which could disrupt network protocol operations and/or interrupt traffic.

This issue does not affect IPv4 DDoS protection.

This issue affects MX Series and EX9200 Series with Trio-based PFEs (Packet Forwarding Engines), including:

  • 750-028381 MX-MPC1-3D
  • 750-031087 MX-MPC1-3D
  • 750-028395 MX-MPC1-3D-Q
  • 750-031092 MX-MPC1-3D-Q
  • 750-038489 MX-MPC1E-3D
  • 750-038490 MX-MPC1E-3D-Q
  • 750-031089 MX-MPC2-3D
  • 750-028393 MX-MPC2-3D
  • 750-028391 MX-MPC2-3D-Q
  • 750-031088 MX-MPC2-3D-Q
  • 750-028394 MX-MPC2-3D-EQ
  • 750-031090 MX-MPC2-3D-EQ
  • 750-024884 MX-MPC2-3D-EQ
  • 750-038491 MX-MPC2E-3D
  • 750-038493 MX-MPC2E-3D-Q
  • 750-038492 MX-MPC2E-3D-EQ
  • 750-028467 MPC-3D-16XGE-SFPP
  • 711-031594 CHAS-MX80-S
  • 711-031603 CHAS-MX80-48T-S
  • 711-038215 CHAS-MX5-T-S
  • 711-038213 CHAS-MX10-T-S
  • 711-038211 CHAS-MX40-T-S
  • 711-038634 CHAS-MX80-T-S

This issue affects Juniper Networks Junos OS on MX series and EX9200 Series:

  • 17.2 versions prior to 17.2R3-S4;
  • 17.2X75 versions prior to 17.2X75-D102, 17.2X75-D110;
  • 17.3 versions prior to 17.3R3-S8;
  • 17.4 versions prior to 17.4R2-S11, 17.4R3-S2;
  • 18.2 versions prior to 18.2R2-S7, 18.2R3, 18.2R3-S3;
  • 18.2X75 versions prior to 18.2X75-D30;
  • 18.3 versions prior to 18.3R2-S4, 18.3R3-S2.

The DDoS feature is enabled by default, there is no specific config stanza required to enable DDoS protection, however it can be manually disabled.

To check if DDOS protection is enabled, the administrator can issue the following command:

user@host> show ddos-protection statistics
DDOS protection global statistics:
Policing on routing engine: Yes
Policing on FPC: Yes

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was found during internal product security testing or research.

This issue has been assigned CVE-2020-1665.


The following software releases have been updated to resolve this specific issue: Junos OS 17.2R3-S4, 17.2X75-D102, 17.2X75-D110, 17.3R3-S8, 17.4R2-S11, 17.4R3-S2, 18.2R2-S7, 18.2R3, 18.2R3-S3, 18.2X75-D30, 18.3R2-S4, 18.3R3-S2, 18.4R1, and all subsequent releases.

This issue is being tracked as 1377899.


There are no viable workarounds for this issue.

Software releases or updates are available for download at
Modification History:
2020-10-14: Initial Publication
2021-06-15: Expanded list of known Trio-based PFEs

CVSS Score:
5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
Severity Level:
Severity Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

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