Bug ID 1629857: Unexpected junk characters in ASM websocket traffic.

Last Modified: Feb 28, 2025

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

Known Affected Versions:
17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1

Fixed In:
17.5.0

Opened: Aug 20, 2024

Severity: 3-Major

Symptoms

The websocket traffic request field contains junk characters that require attention.

Impact

The request field in logging is wrong

Conditions

- Websocket logging with request field - The websocket connection uses compression - The compression uses context takeover, which increases subsequent frames' compression rate ( same data size but smaller frame length, thanks to context takeover ).

Workaround

Disable websocket compression. For instance, disable WebSocket compression by removing the "Sec-WebSocket-Extensions" header from the upgrade request HTTP request. This can be achieved through available options, Websocket profile, ASM configuration, or an iRule.

Fix Information

Need to fix the code logic in the request field population.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips