Bug ID 1070737: AFM does not detect NXDOMAIN attack at virtual context when DNS cache is activated.

Last Modified: Jan 20, 2023

Bug Tracker

Affected Product:  See more info
BIG-IP AFM(all modules)

Known Affected Versions:
15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3

Opened: Dec 29, 2021
Severity: 3-Major

Symptoms

When the DNS cache is activated, the NXDOMAIN DoS vector does not increase for the virtual server context. As a result, NXDOMAIN flood attack is never detected/mitigated at the virtual server context. Note this does not happen with other vectors like DNS A query flood attack, only for NXDOMAIN.

Impact

NXDOMAIN flood attack is never detected/mitigated at virtual server context.

Conditions

Issue is only seen When DNS cache is activated and for NXDOMAIN Dos Vector.

Workaround

N/A

Fix Information

None

Behavior Change