ASUS RT-AC68U Firmware version 3.0.0.4.385.20585

[wouterv]

Anyone else had/fixed this issue? - https://www.snbforums.com/threads/p...u-3-0-0-4-385_20585-update.64755/#post-594663

No, only the WLCEVENTD messages and daily ahs messages which are both the new standard since a few firmware versions.
The issue is reported for the RT-AC88U, this topic is regarding the RT-AC68U.

 

[RMerlin]

Since this upgrade, I am now receiving a captcha image challenge with virtually every logon. Sent negative feedback to ASUS. Logon is enable locally only and there are no invalid password attempts in between logons.

Make sure you don't have something on your LAN hammering the router's port 80, and that you didn't open your webui to the Internet. The captcha only shows up after a number of failed connection attempts.

 

[wouterv]

No, definitely not open to the internet and no indication in the log whatsoever. If I log out of the router, close the browser tab, open a new tab, I'm presented with the captcha again. Reverted to the prior firmware. No issue now.

I do not manage to break it here, when was the captcha feature introduced?
With successful logins I do never see the captcha.
After the 3th false login, the router presents the captcha.
Then after a successful login with captcha it stays away as long as you enter the proper credentials.

 

[wouterv]

It looks as if it was introduced in either 20490 or 20585. I skipped 20490, so I can't tell directly, but I see comments elsewhere about the captcha issue that date from May, so it may have been 20490. ASUS' change log is never very comprehensive.

I see a completely different behavior. I'm initially presented with the captcha...if I log out and log in again in the same browser tab, I don't see it again, but if I close the tab and open a new one, I'm presented with the captcha again, even with no intervening invalid logon attempts.

At this point, I'm back running version 20433. My network has 1 user and 7 devices. I don't access my network remotely, so I see no need for the extra hassle.

All I can tell is that I didn't see the captcha until I did some testing before I posted my reply here a few days ago.
My RT-AC68U is around for a couple of years and keeps pace with Asus stock firmware, I wasn't even aware the captcha was also introduced on this model (I saw the captcha posts around here for other router models), and I almost daily login to the router GUI.
Can only conclude the captcha feature works as intended here and keeps itself quiet as long as logins succeed.
I don't know if the mechanism also got triggered after failed Samba, FTP, Telnet or SSH logins.

[EDIT]
At least a failed SSH login does not cause the captcha for login to the GUI.
A failed SSH login blocks SSH for certain time and does generate the following System Log message:

Jun 29 19:49:38 dropbear[20667]: Login attempt for nonexistent user from 192.168.1.169:63234