QID 44028

Juniper Junos is the network operating system used in Juniper Networks hardware systems.

A Use After Free vulnerability in the Layer 2 Address Learning Manager (l2alm) of Juniper Networks Junos OS on QFX Series allows an adjacent attacker to cause the Packet Forwarding Engine to crash and restart, leading to a Denial of Service (DoS).The PFE may crash when a lot of MAC learning and aging happens, but due to a Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization) that is outside the attackers direct control.

Affected Junos versions:
Juniper Networks Junos OS on QFX Series Juniper Networks Junos OS versions prior to 19.4R3-S10 on QFX Series
20.2 versions prior to 20.2R3-S7
20.3 versions prior to 20.3R3-S6
20.4 versions prior to 20.4R3-S5
21.1 versions prior to 21.1R3-S4
21.2 versions prior to 21.2R3-S3
21.3 versions prior to 21.3R3-S3
21.4 versions prior to 21.4R3
22.1 versions prior to 22.1R3
22.2 versions prior to 22.2R2
QID detection logic: (Authenticated)
It checks for vulnerable Junos OS version.

Note: This QID does not checks for only affected versions hence set to practice.

Successful exploitation allows a network-based, unauthenticated attacker to cause Denial of Service (DoS).