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Logon ssh com Falha (Red Hat Enterprise Linux Server 5)

Microsoft.ACS.Linux.RHEL.5.Ssh.Failed (Rule)

Regra para coletar eventos relacionados a logons ssh com falha

Knowledge Base article:

Resumo

Foi detectado um comando ssh malsucedido nos arquivos de log do sistema.

Causas

Não foi concedido ao usuário acesso ao sistema remotamente. Este monitor permite que os administradores de sistemas controlem o uso de 'ssh'.

Resoluções

A descrição do alerta e/ou do item de dados de saída contém informações sobre o evento encontrado. Se a atividade parecer suspeita, verifique os detalhes do evento relacionado e todos os outros eventos que ocorreram por volta do horário desse evento.

Element properties:

TargetMicrosoft.ACS.Linux.RHEL.5.ACSEndPoint
CategoryEventCollection
EnabledTrue
Alert GenerateFalse
RemotableTrue

Member Modules:

ID Module Type TypeId RunAs 
EventDS DataSource Microsoft.Unix.SCXLog.Privileged.Datasource Default
WA WriteAction Microsoft.ACS.Unix.SecureEventLogWriter Default

Source Code:

<Rule ID="Microsoft.ACS.Linux.RHEL.5.Ssh.Failed" Enabled="true" Target="Microsoft.ACS.Linux.RHEL.5.ACSEndPoint" Remotable="true">

  <Category>EventCollection</Category>

  <DataSources>

    <DataSource ID="EventDS" TypeID="Unix!Microsoft.Unix.SCXLog.Privileged.Datasource">

      <Host>$Target/Host/Property[Type="Unix!Microsoft.Unix.Computer"]/NetworkName$</Host>

      <LogFile>/var/log/secure</LogFile>

      <!-- [TYPE] Redhat5 SSH False -->

      <!-- [INPUT] Jul 31 20:06:04 scxcore-rhel50-01 sshd[16762]: Failed password for jonas from 172.30.181.43 port 2898 ssh2 -->

      <!-- [INPUT] Jul 31 20:06:25 scxcore-rhel50-01 sshd[16764]: Failed password for root from 172.30.181.43 port 2899 ssh2 -->

      <!-- [INPUT] Jul 31 20:06:40 scxcore-rhel50-01 sshd[16766]: Failed password for invalid user kalle from 172.30.181.43 port 2900 ssh2 -->

      <!-- [EXPECTED] date="Jul 31 20:06:04"; hostname="scxcore-rhel50-01"; process="sshd"; processId="16762"; user="jonas"; clientHost="172.30.181.43" -->

      <!-- [EXPECTED] date="Jul 31 20:06:25"; hostname="scxcore-rhel50-01"; process="sshd"; processId="16764"; user="root"; clientHost="172.30.181.43" -->

      <!-- [EXPECTED] date="Jul 31 20:06:40"; hostname="scxcore-rhel50-01"; process="sshd"; processId="16766"; user="kalle"; clientHost="172.30.181.43" -->

      <RegExpFilter>\s+sshd\[[[:digit:]]+\]: Failed password for (invalid user )?\S+ from \S+</RegExpFilter>

    </DataSource>

  </DataSources>

  <WriteActions>

    <WriteAction ID="WA" TypeID="ACS.Unix!Microsoft.ACS.Unix.SecureEventLogWriter">

      <RegExp>(?'date'\S+\s+\d+\s+\d+:\d+:\d+)\s+(?:\S+:)?(?'hostname'\S+)\s+(?'process'sshd)\[(?'processId'\d+)\]: Failed password for (?:invalid user )?(?'user'\S+) from (?'clientHost'\S+)</RegExp>

      <EventType>0</EventType>

      <EventId>27003</EventId>

    </WriteAction>

  </WriteActions>

</Rule>