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Failed ssh login (Red Hat Enterprise Linux Server 5)

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

Rule to collect events for failed ssh login

Knowledge Base article:

Summary

An unsuccessful ssh command has been detected in the system log files.

Causes

User was not granted access to the system remotely. This monitor allows system administrators to track 'ssh' usage.

Resolutions

The description of the alert and/or the output data item contains information on the event encountered. If the activity appears suspicious, please check the associated event details and any other events that happened around the time of this event.

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>