On Wed, Sep 24, 2025 at 1:26 PM Michael Jumper <[email protected]> wrote:

> On September 24, 2025 5:52:20 AM PDT, Nick Couchman <[email protected]>
> wrote:
> >On Mon, Sep 22, 2025 at 7:22 PM Ares Li <[email protected]> wrote:
> >
> >> Hello community,
> >>
> >> I know in 1.6.0 the failed login attempts will ban the IP by default,
> but
> >> this would not make sense in the scenario that users are under VPN. I am
> >> wondering if we (will) support banning username instead of a public
> facing
> >> IP.
> >>
> >>
> >Hello, Ares,
> >Your point is well-taken that it would probably be useful to have a
> >feature, either in the JDBC module or in the Ban module, to lock out
> >accounts based on failed login attempts, as is common for authentication
> >systems. I actually thought we already had that functionality in the JDBC
> >account, but apparently I was mistaken, so I think a feature request and
> >work to implement that would be in order.
> >
>
> If considering username instead of IP, I would be concerned that a
> malicious user could trivially leverage that behavior to deny a specific,
> known user access to Guacamole. There'd need to be some reliable,
> out-of-band mechanism for the real user to come back, verify themselves,
> and regain access to their account.
>
>
Good points - I didn't think about that. I was thinking about the fact that
it's more likely that a real attacker will try multiple usernames to try to
circumvent any sort of a per-user lockout, but didn't think about there
being certain situations where a user is targeted.


> We could consider _both_ username and IP, optionally flagging repeated
> failed attempts to authenticate as problematic only if also against the
> same account. That might avoid both cases, but would be arguably weaker
> than banning purely IPs.
>
>
I think having this as an option would be good - I do think the default of
the IP-based approach is probably good for most situations, particularly
where Guacamole is exposed to the Internet, as it avoids both the
short-fall of targeting a particular user and that of attacking the system
via multiple user accounts. But, I do see the original use-case of having
situations where you may lack visibility into the actual source IP address
of the clients.

-Nick

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