Bug ID 1505257: False positive with "illegal base64 value" for Authorization header

Last Modified: Jul 03, 2025

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

Known Affected Versions:
17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 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: Feb 07, 2024

Severity: 4-Minor

Symptoms

False positive "illegal base64 value" is detected

Impact

A false positive is detected.

Conditions

The given base64 encoded value is legal base64 but the decoded auth-param is unparsable. Such request triggers "HTTP Protocol Compliance" violation when configured to do so and it is indeed triggering, but such request should not trigger "illegal base64 value".

Workaround

None

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips