Yes, thank for the responses and clarification.   True the Basic Auth isn't really a login, as there is no logout per se.

One would suppose from the responses that using .htpasswd and Basic Auth is really a lousy approach to security, since an attacker can just wail away indefinitely trying repeatedly, unless one configured something like fail2ban to cut off repeated attempts.   I was just looking to improve on that if possible.

On Thu, 2011-10-06 at 22:54 +0200, Jeroen Geilman wrote:
On 2011-10-04 14:44, Neal Rhodes wrote:
We have bunches of web applications which use the regular Apache login protection,

Do you mean HTTP Basic Auth, as defined in RFC 2616 ?

and they won't run unless REMOTE_USER is set by the Apache login.  

<Limit GET>
require valid-user

require valid-user

AuthName O-Visitor
AuthUserFile /usr/appl/cgi/.htpasswd

AuthType Basic

Yes, this is HTTP Basic AUTH.
It says so right there.

Looking at improving security, it would seem that it would be much harder to conduct brute-force attacks on these systems if we could configure Apache login to do two things:

You can't.
There is no "login", just an Authorization: header which has to be sent for every page that requires it.

A. Present the CAPTCHA style validation prompt as part of the login, to make it difficult for scripted attacks to proceed;
B. Lockout an individual username in the .htpasswd file after X failed login attempts.

Actual login-ness (a state of logged in being different from a state of not being logged in) must be achieved through non-HTTP means, possibly supported by HTTP features such as cookies.