Bug ID 1920637: Duplicate user-defined Signature Set based on Attack Type is created upon policy import during upgrade

Last Modified: Jun 28, 2025

Affected Product(s):
BIG-IP ASM, Install/Upgrade(all modules)

Known Affected Versions:
16.1.5, 16.1.5.1, 16.1.5.2, 16.1.6, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.5.0, 17.5.1

Opened: Apr 03, 2025

Severity: 3-Major

Symptoms

After an upgrade or a re-import, duplicate signature sets denoted by a "_1" are created containing NULL values instead of empty strings.

Impact

Additional "duplicate" sets are created every time a policy is re-imported. This does not affect any functionality, but does increase the total configuration size, and makes the configuration more difficult to manage.

Conditions

A user-defined signature set has an empty string for the tagged signature filter.

Workaround

You can repair the policy by navigating to “Security ›› Application Security : Policy Building : Learning and Blocking Settings”, clicking on “change”, and choosing the original created sets instead of the duplicated sets. Save, and then apply the policy. The duplicated sets can be deleted after that.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips