phil@amd.UUCP (Phil Ngai) (07/09/84)
What do people think of hanging up the phone if an incorrect login
attempt is made? Coupled with reasonable passwords, that should
provide some security against "wargames" type attacks, don't you think?
Does anyone have such a version available? It'd be easy to do but why
reinvent the wheel?
--
From Joe's Foo bar and grill
Phil Ngai (408) 982-6554 {ucbvax,decwrl,ihnp4,allegra,intelca}!amd!phillat@stcvax.UUCP (Larry Tepper) (07/10/84)
I modified login for both V7 and 4.1BSD to do just that (i. e.
hang up after a bad password is typed). My version gives you
three chances before exiting. It waits 20 seconds before it
exits, to slow down automated password breakers.
Logging in over over a dial-up also requires the user to type a
second password (the `External Security' password -- remember
this from fortune?). A dial-up is recognized as a login terminal
whose name starts with "ttyd". The 2nd password is determined by
the dummy user name `dialup' in /etc/passwd.
Just as the original login always asks for a password, even when
given an invalid login name, so too does this version always ask
for the external security password, even when the 1st password
is wrong. There is an exception, namely:
To make life easier for uucp, the 2nd password is not requested
over a dial-up if the user's login shell is "/usr/lib/uucp/uucico"
(except when the 1st password is incorrectly given). This seemed
the safest way of ensuring that a user really is uucp.
Notification of all logins attempts over a dial-up, successful or
not, are sent to the system console. A system administrator can
look at the console sheets for suspicious activity.
It would be impossible to post the sources, even diffs, to the net
without violating the UNIX license agreement. Would someone like
to comment on the legalities of mailing it electronically assuming
I've been given hard evidence of the receiver's UNIX source license?
--
{ihnp4 hao philabs sdcrdcf ucbvax!nbires}!stcvax!lat Larry Tepper
Storage Technology, MD-3T, Louisville, CO 80028 303-673-5435laura@utzoo.UUCP (Laura Creighton) (07/11/84)
The phone lines in Santa Clara must be much better than the ones here. (And Phil Ngai must have better modems than a lot I've seen). I think that for those of us that have to fight noise on the way to our machines an automatic ``hang-up the phone'' would be excruciating. Laura Creighton utzoo!laura
trt@rti-sel.UUCP (07/13/84)
If your phone lines are so bad that more than three login attempts are needed, I shudder at the carnage that must ensue once you do get logged in! I suppose Phil Ngai/Larry Tepper could check for apparently trashed input and not count such against you. That is better than weakening their login security, which is after all the last chance to keep some random from logging into the system and becoming superuser. Some other security details that should be considered: * Beware of giving out the external password over the phone! * It would be nice to permit the "old" external password (with a warning), so it can be changed regularly without causing too much grief. * Failed-attempt logging should probably be implemented by Someone Else. Naive logging might result in someone's password being published as an "invalid login name". Sophisticated logging can be worse, because if something awful happens and it was logged and you overlooked it ... bye bye system administrator. Tom Truscott
zemon@felix.UUCP (Art Zemon) (07/13/84)
To hang up the phone after N incorrect login attempts, just
make /bin/login exit. That isn't much to "reinvent".
Art Zemon
FileNet Corp.