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  1. #1

    Padrão denyhosts não está bloqueando ataques

    Ola.

    Notei uma certa falha no funcionamento do denyhosts. Mesmo que o denyhosts bloqueie uma tentativa de invasão do ip 200.200.200.200 com usuario "abobrinha" eu continuo recebendo atacques do ip 200.200.200.200 por qu ele tenta com usuários diferentes. O que eu posso fazer nesse caso ? Vou postar um pedaço do meu messages pra voces terem uma idéia:

    tac /var/log/messages |grep sshd |more
    Jan 23 19:10:25 gia sshd[9705]: Failed password for invalid user test from 3Com VCX Connect port 22872 ssh2
    Jan 23 19:10:25 gia sshd[9705]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:25 gia sshd[9705]: Invalid user test from 3Com VCX Connect
    Jan 23 19:10:23 gia sshd[9703]: Failed password for invalid user test from 3Com VCX Connect port 21722 ssh2
    Jan 23 19:10:23 gia sshd[9703]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:23 gia sshd[9703]: Invalid user test from 3Com VCX Connect
    Jan 23 19:10:20 gia sshd[9701]: Failed password for invalid user hermes from 3Com VCX Connect port 21487 ssh2
    Jan 23 19:10:20 gia sshd[9701]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:20 gia sshd[9701]: Invalid user hermes from 3Com VCX Connect
    Jan 23 19:10:18 gia sshd[9698]: Failed password for invalid user cyrus from 3Com VCX Connect port 20149 ssh2
    Jan 23 19:10:18 gia sshd[9698]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:18 gia sshd[9698]: Invalid user cyrus from 3Com VCX Connect
    Jan 23 19:10:16 gia sshd[9696]: Failed password for invalid user carlos from 3Com VCX Connect port 19962 ssh2
    Jan 23 19:10:16 gia sshd[9696]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:16 gia sshd[9696]: Invalid user carlos from 3Com VCX Connect
    Jan 23 19:10:13 gia sshd[9694]: Failed password for root from 3Com VCX Connect port 19251 ssh2
    Jan 23 19:10:11 gia sshd[9692]: Failed password for invalid user admin from 3Com VCX Connect port 18510 ssh2
    Jan 23 19:10:11 gia sshd[9692]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:11 gia sshd[9692]: Invalid user admin from 3Com VCX Connect
    Jan 23 19:10:08 gia sshd[9690]: Failed password for invalid user toto from 3Com VCX Connect port 17136 ssh2
    Jan 23 19:10:08 gia sshd[9690]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:08 gia sshd[9690]: Invalid user toto from 3Com VCX Connect
    Jan 23 19:10:06 gia sshd[9684]: Failed password for invalid user wrestling from 3Com VCX Connect port 17021 ssh2
    Jan 23 19:10:06 gia sshd[9684]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:06 gia sshd[9684]: Invalid user wrestling from 3Com VCX Connect
    Jan 23 19:10:04 gia sshd[9679]: Failed password for invalid user admin from 3Com VCX Connect port 16896 ssh2
    Jan 23 19:10:04 gia sshd[9679]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:04 gia sshd[9679]: Invalid user admin from 3Com VCX Connect
    Jan 23 19:10:01 gia sshd[9661]: Failed password for invalid user admin from 3Com VCX Connect port 16194 ssh2
    Jan 23 19:10:01 gia sshd[9661]: error: Could not get shadow information for NOUSER
    Jan 23 19:10:01 gia sshd[9661]: Invalid user admin from 3Com VCX Connect
    Jan 23 19:09:59 gia sshd[9659]: Failed password for root from 3Com VCX Connect port 15457 ssh2
    Jan 23 19:09:57 gia sshd[9657]: Failed password for invalid user moshutzu from 3Com VCX Connect port 14731 ssh2
    Jan 23 19:09:57 gia sshd[9657]: error: Could not get shadow information for NOUSER
    Jan 23 19:09:57 gia sshd[9657]: Invalid user moshutzu from 3Com VCX Connect
    Jan 23 19:09:54 gia sshd[9655]: Failed password for invalid user valas from 3Com VCX Connect port 13984 ssh2
    Jan 23 19:09:54 gia sshd[9655]: error: Could not get shadow information for NOUSER
    Jan 23 19:09:54 gia sshd[9655]: Invalid user valas from 3Com VCX Connect
    Jan 23 19:09:52 gia sshd[9653]: Failed password for root from 3Com VCX Connect port 13265 ssh2
    Jan 23 19:09:50 gia sshd[9651]: Failed password for root from 3Com VCX Connect port 12550 ssh2
    Jan 23 19:09:47 gia sshd[9649]: Failed password for invalid user test from 3Com VCX Connect port 11824 ssh2
    Jan 23 19:09:47 gia sshd[9649]: error: Could not get shadow information for NOUSER
    Jan 23 19:09:47 gia sshd[9649]: Invalid user test from 3Com VCX Connect
    Jan 23 19:09:45 gia sshd[9647]: Failed password for invalid user test from 3Com VCX Connect port 11099 ssh2


    Sendo que o ip 3Com VCX Connect ja foi "bloqueado" pelo denyhosts e já consta no /etc/hosts.deny, porém, ele foi bloqueado com um outro usuário. Tem alguma maneira de eu bloquear o ip 3Com VCX Connect já na segunda tentativa de ataque, mesmo que esse host tente me atacar com usuários diferentes ?


    []'s, Renato

  2. #2

    Padrão

    Amigo!

    Posta ae seu hosts.deny pq pelo q eu sabia ele bloqueava acesso de vez a porta nao sabia disso por usuario!

  3. #3

    Padrão

    Abaixo segue meu hosts.deny e mais abaixo meu denyhosts.cfg

    hosts.deny

    ALL:ALL EXCEPT 127.0.0.1ENY
    # DenyHosts: Thu Jan 24 02:28:02 2008 | ALL: 190.2.29.181
    ALL: 190.2.29.181
    # DenyHosts: Thu Jan 24 03:52:02 2008 | ALL: 194.250.47.30
    ALL: 194.250.47.30
    # DenyHosts: Thu Jan 24 04:16:02 2008 | ALL: 150.183.249.96
    ALL: 150.183.249.96
    # DenyHosts: Thu Jan 24 06:52:01 2008 | ALL: 201.48.249.23
    ALL: 201.48.249.23
    # DenyHosts: Thu Jan 24 07:30:04 2008 | ALL: 202.70.86.69
    ALL: 202.70.86.69
    # DenyHosts: Thu Jan 24 09:56:03 2008 | ALL: 195.19.151.8
    ALL: 195.19.151.8



    denyhosts.cfg
    # Mandrake, FreeBSD or OpenBSD:
    SECURE_LOG = /var/log/denyhosts

    HOSTS_DENY = /etc/hosts.deny

    PURGE_DENY = 4w

    PURGE_THRESHOLD = 0

    DENY_THRESHOLD_INVALID = 1

    DENY_THRESHOLD_VALID = 2

    BLOCK_SERVICE = ALL

    DENY_THRESHOLD_ROOT = 1

    DENY_THRESHOLD_RESTRICTED = 1

    WORK_DIR = /usr/share/denyhosts/data

    SUSPICIOUS_LOGIN_REPORT_ALLOWED_HOSTS=YES

    HOSTNAME_LOOKUP=YES

    LOCK_FILE = /var/lock/subsys/denyhosts

    ADMIN_EMAIL = [email protected]

    SMTP_HOST = localhost
    SMTP_PORT = 25

    SMTP_FROM = DenyHosts < nobody@localhost>

    SMTP_SUBJECT = DenyHosts Report

    ALLOWED_HOSTS_HOSTNAME_LOOKUP=yes

    AGE_RESET_VALID=5d

    AGE_RESET_ROOT=25d

    AGE_RESET_RESTRICTED=25d

    AGE_RESET_INVALID=10d

    DAEMON_LOG = /var/log/denyhosts

    DAEMON_LOG_TIME_FORMAT = %b %d %H:%M:%S

    DAEMON_SLEEP = 30s

    DAEMON_PURGE = 3d

    SYNC_SERVER = http://xmlrpc.denyhosts.net:9911

    SYNC_INTERVAL = 1d

    SYNC_UPLOAD = yes

  4. #4

    Padrão

    nao vi ae onde vc estava bloqueando por usuario.
    olha seu hosts.allow para ver se nao está liberando.

    vc nao acha melhor fazer isso por firewall não?

    e nao é melhor bloquear tudo pelo hosts.deny e depois sair liberando no hosts.allow?
    Última edição por andersoneduardo; 24-01-2008 às 10:42.