CVE-2021-31379 Information

Description

An Incorrect Behavior Order vulnerability in the MAP-E automatic tunneling mechanism of Juniper Networks Junos OS allows an attacker to send certain malformed IPv4 or IPv6 packets to cause a Denial of Service (DoS) to the PFE on the device which is disabled as a result of the processing of these packets. Continued receipt and processing of these malformed IPv4 or IPv6 packets will create a sustained Denial of Service (DoS) condition. This issue only affects MPC 7/8/9/10/11 cards when MAP-E IP reassembly is enabled on these cards. An indicator of compromise is the output: FPC [\FPC ID\ e.g. �] PFE PFE ID e.g. \1] : Fabric Disabled Example: FPC 0 PFE 1 : Fabric Disabled when using the command: show chassis fabric fpcs An example of a healthy result of the command use would be: user@device-re1> show chassis fabric fpcs Fabric management FPC state: FPC 0 PFE 0 Plane 0: Plane enabled Plane 1: Plane enabled Plane 2: Plane enabled Plane 3: Plane enabled Plane 4: Plane enabled Plane 5: Plane enabled Plane 6: Plane enabled Plane 7: Plane enabled This issue affects: Juniper Networks Junos OS on MX Series with MPC 7/8/9/10/11 cards when MAP-E IP reassembly is enabled on these cards. 17.2 version 17.2R1 and later versions; 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S12 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R2-S6 18.2R3-S3; 18.3 versions prior to 18.3R2-S4 18.3R3-S1; 18.4 versions prior to 18.4R1-S8 18.4R2-S5 18.4R3; 19.1 versions prior to 19.1R1-S6 19.1R2-S2 19.1R3; 19.2 versions prior to 19.2R1-S5 19.2R2; 19.3 versions prior to 19.3R2-S5 19.3R3. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R1.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Reference

https://kb.juniper.net/JSA11247 https://www.juniper.net/documentation/en_US/junos/topics/topic-map/map-e-configuring.html

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

7.5