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Hacking and Security => Hacking and Security => : 650m January 12, 2015, 06:09:31 PM

: SMTP Brute Force / Dictionary Attack
: 650m January 12, 2015, 06:09:31 PM
Hi,

I have some issues with smtp brute forcing:

I tried to brute force my own gmail account with hydra (Im using Kali Linux)

I have a little wordlist where I included the password of the account.

The probem is that hydra sometimes show different positive password matches.

My syntax:

:
hydra -S -l account@gmail.com -P wordlist.txt -e ns -V -s 465 smtp.gmail.com smtp
As I said, the process works but sometimes I get false positives...

Can someone explain how to fix this or are there good alternatives for smtp brute forcing?
: Re: SMTP Brute Force / Dictionary Attack
: Syntax990 January 12, 2015, 08:19:50 PM
When you launch an attack on a Gmail account, Google take this as an attack on them.

This attack is effective against a small time SMTP network but not a huge enterprise network who get these kinds of attacks every day.
: Re: SMTP Brute Force / Dictionary Attack
: 650m January 12, 2015, 11:58:24 PM
So you want to say, that these false positives are forced by Google?
: Re: SMTP Brute Force / Dictionary Attack
: d4rkcat January 13, 2015, 12:30:03 AM
So you want to say, that these false positives are forced by Google?

most likely.
It's a smart way of fucking with brute forcers.
: Re: SMTP Brute Force / Dictionary Attack
: madf0x January 13, 2015, 07:02:23 AM
And if it isn't thats still a nifty idea. Not sure when the next time comes around that I'd have to restrict bruteforce attempts, but its a neat idea to try.

As for OP, one of the better way to do bruteforcing against some anti-bruteforce measures is to use a smaller wordlist, like 3 password attempts small, and then use a LARGE potential users list. Many anti-bruteforce measures these days don't limit against user attempts. Granted this is only useful if you need to target a bunch of low hanging fruit for secondary purposes or if you are targeting a large organization. Oh and be sure to check for some sort of password policy. Wasting an attempt on Password123 won't help if they need a symbol, then youd use P@ssword123 ;P
: Re: SMTP Brute Force / Dictionary Attack
: 650m January 13, 2015, 08:23:52 AM
And if it isn't thats still a nifty idea. Not sure when the next time comes around that I'd have to restrict bruteforce attempts, but its a neat idea to try.

As for OP, one of the better way to do bruteforcing against some anti-bruteforce measures is to use a smaller wordlist, like 3 password attempts small, and then use a LARGE potential users list. Many anti-bruteforce measures these days don't limit against user attempts. Granted this is only useful if you need to target a bunch of low hanging fruit for secondary purposes or if you are targeting a large organization. Oh and be sure to check for some sort of password policy. Wasting an attempt on Password123 won't help if they need a symbol, then youd use P@ssword123 ;P
Well, if you targeting  one particular account, a 3 password list won't help at all :D

I think for a successful brute force attack it needs an exploit which allows a large attempts of password tries.

Another question: what do you guys thing about brute forcing via VPN ?
: Re: SMTP Brute Force / Dictionary Attack
: d4rkcat January 13, 2015, 03:17:21 PM
And if it isn't thats still a nifty idea. Not sure when the next time comes around that I'd have to restrict bruteforce attempts, but its a neat idea to try.

I'm pretty sure one of the google devs saw this talk at defcon. (https://www.youtube.com/watch?v=I3pNLB3Cq24)
That's where I first heard of this idea, it's neat.

@OP Brute forcing is so boring, so 1995.
It doesn't matter if you use a VPN it is still coming from one IP address it is the exact same thing apart from harder to track back to you. I guess if you really have to you could use a huge list of proxies and cycle through them.
I would personally go for social engineering or spear phishing.
: Re: SMTP Brute Force / Dictionary Attack
: madf0x January 14, 2015, 03:42:29 AM
Well, if you targeting  one particular account, a 3 password list won't help at all :D

No shit lol that was literally my point. If you want to try to use an online bruteforce method, you'll have to broaden your horizons a little bit. The whole point instead of running the gambit against one joe in an organization, you'd go after everyone and use the lowest hanging fruits as a foot closer to your target. You silly.