Bug ID 1624565: "Illegal login attempt" violation is detected for valid login request with Authentication Type different from Basic/Digest

Last Modified: Apr 28, 2025

Affected Product(s):
BIG-IP ASM(all modules)

Fixed In:
17.5.0

Opened: Aug 07, 2024

Severity: 3-Major

Symptoms

An "Illegal login attempt" violation is triggered for a request to login pages when authentication type is different from Basic/Digest, for example HTML Form

Impact

A valid login request to the login page will be blocked due to an "Illegal login attempt" violation

Conditions

-- Enabled Alarm and Block flags for "Illegal login attempt" violation and login page with Authentication -- Type is not set to Basic/Digest

Workaround

None

Fix Information

1) Imported policy with enabled Alarm and Block flags for "Illegal login attempt" violation and login page "/login.php" with Authentication Type = HTML Form, Username=user, Password=pass 2) Sent request: GET /login.php?user=test&pass=1234 Results before fix: Request is blocked with an "Illegal login attempt" violation Results after fix: No violation detected

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips