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Brute force attack

Discussion in 'Security' started by hifi_ninja, Apr 7, 2008.

  1. hifi_ninja

    hifi_ninja Member

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    Hi,
    Im a bit nervous about a brute force attack occurring right now on my server...
    (obs. sorry for my broken english)

    I received a lot of emails saying:
    login failures attempts to account

    I checked the cPHulk and found the IP and blocked it using APF firewall
    I set the cPHulk with the following:

    Configure Settings
    IP Based Brute Force Protection Period in minutes: 30
    Brute Force Protection Period in minutes: 35
    Maximum Failures By Account: 15
    Maximum Failures Per IP: 8
    Maximum Failures Per IP before IP is blocked for two week period: 20
    Extend account lockout time upon additional authentication failures: Y
    Send notification when brute force user is detected: Y


    But, what's frightening me :eek: is that the brute force is trying the exact user names os my clients... How could it know that? Did I got cracked in a way the cracker could know only the real usernames but not the passwords? :confused:

    Thanks! :eek:
    Henrique.
     
  2. nyjimbo

    nyjimbo Well-Known Member

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    Its possible someone who has shell access got hold of the password file, without the actual passwords and is trying to hack that. Years ago we had a customer on a box we that offered shell access on and he went and grabbed the /etc/passwd file, weeks later came back and started to try to hack them with a script. Not sure what he was trying to do but he was doing it. Also its possible a spammer attacked your machine with emails to the servers domain name and found results of real account names (no undeliverable returns) and is trying to hack that.
     
  3. Kent Brockman

    Kent Brockman Well-Known Member

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    Twitter:
    Does the usernames of your accounts differ from the domain name their belongs to? i.e: domain: onedomain.com ; username: onedomai

    That also gives a bit of help for crackers and should be aware of.

    Like Jimbo says, I also seen logged (using Logwatch) login attempts using usernames of email accounts currently being spammed. for such brute force attacks, we are lowering their incidence using the (D)DoS-Deflate script (http://deflate.medialayer.com/) ;)
     
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