That's a good idea, although I wonder if perhaps determined attackers aren't already using
botnets for this kind of thing to spread the attack-source IPs around.
(Fail2ban blocks the IP of repeated failed-password attempts. The question is whether an
attacker would run out of IPs before running out of passwords to try - yet another argument
for strong passwords.)
Brute-Force SSH Server Attacks Surge (InformationWeek)
Posted May 14, 2008 16:20 UTC (Wed) by ssam (subscriber, #46587)
[Link]
4 billion ip address, biggest botnets are of the order of 1 million machines. the default on
denyhosts is something like 10 fails per IP address.
there are 26^5 = 11 million, 5 character lowercase passwords
there are 26^7 = 8 billion, 7 character lowercase passwords
Ubuntu does not install an ssh server by default. which consumer distros do?
Ubuntu also, by default does not have a root user, so if you want to brute force you have to
guess a username as well.
crazy idea:
what if, once in 10 times, when an ssh login failed, the ssh server pretended that it has
succeeded, and gave a pretend shell that did nothing. would that confuse the crackers?
Brute-Force SSH Server Attacks Surge (InformationWeek)
Posted May 14, 2008 16:37 UTC (Wed) by pr1268 (subscriber, #24648)
[Link]
what if, once in 10 times, when an ssh login failed, the ssh server pretended that it has succeeded, and gave a pretend shell that did nothing. would that confuse the crackers?
What you describe sounds like a variation of a honeypot. Interesting concept, IMO, but I'm certain that whatever functionality incorporated in this "pretend" shell would necessarily be a small subset of what a real shell could contain.
Taking your idea further, how about a completely "functional" pretend shell whose programs and commands are all faked as well.... Sounds like a lot of work just to snoop on the bad guys, but a peculiarly interesting idea nevertheless...
Brute-Force SSH Server Attacks Surge (InformationWeek)
Posted May 14, 2008 18:28 UTC (Wed) by smoogen (subscriber, #97)
[Link]
Yes they have been doing this for a while.. The latest set of attacks are using it more. I
have seen attacks where machine A goes for account "foo, foo1, foo2" and then machine B does
"foo3, foo4, foo5" and then machine C goes for "foo6, goo, goo1" and machine A tries again
(well its a lot bigger than that but just logging in once and coming back an hour later is
enough to get past most public ssh servers fail2ban systems.) Add onto that a lot of users
think Q1w2e3r4 is a good password and are sure to get some account on a university or big ISP
sometime.