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the-wabbit
Asked: 2013-07-19 07:40:38 +0800 CST

Unexpected results from an XML query filter for security event log

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Folks,

I am trying to craft a custom XML / Xpath filter to the Windows Event Log viewer to exclude the countless "SYSTEM" Logons from the security log's view. I have managed to get this far with the help of the Technet blog on XML filtering:

<QueryList>
  <Query Id="0" Path="Security">
    <Select Path="Security">
      *[System[(EventID=4624)]] 
      and
      *[EventData[Data[@Name='TargetUserSid'] and  (Data!='S-1-5-18')]]
</Select>
  </Query>
</QueryList>

But against all expectations I still have events like this one (among others, of course) in the view:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-A5BA-3E3B0328C30D}" />
    <EventID>4624</EventID>
    <Version>0</Version>
    <Level>0</Level>
    <Task>12544</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8020000000000000</Keywords>
    <TimeCreated SystemTime="2013-07-18T15:12:55.797049800Z" />
    <EventRecordID>199135861</EventRecordID>
    <Correlation />
    <Execution ProcessID="496" ThreadID="3028" />
    <Channel>Security</Channel>
    <Computer>SBS.domain.local</Computer>
    <Security />
  </System>
  <EventData>
    <Data Name="SubjectUserSid">S-1-0-0</Data>
    <Data Name="SubjectUserName">-</Data>
    <Data Name="SubjectDomainName">-</Data>
    <Data Name="SubjectLogonId">0x0</Data>
    <Data Name="TargetUserSid">S-1-5-18</Data>
    <Data Name="TargetUserName">SBS$</Data>
    <Data Name="TargetDomainName">DOMAIN</Data>
    <Data Name="TargetLogonId">0x684af79a</Data>
    <Data Name="LogonType">3</Data>
    <Data Name="LogonProcessName">Kerberos</Data>
    <Data Name="AuthenticationPackageName">Kerberos</Data>
    <Data Name="WorkstationName">
    </Data>
    <Data Name="LogonGuid">{9D5E970C-928D-E3FD-8D96-09044670F33E}</Data>
    <Data Name="TransmittedServices">-</Data>
    <Data Name="LmPackageName">-</Data>
    <Data Name="KeyLength">0</Data>
    <Data Name="ProcessId">0x0</Data>
    <Data Name="ProcessName">-</Data>
    <Data Name="IpAddress">fe80::cc18:cb50:1710:c2a7</Data>
    <Data Name="IpPort">6413</Data>
  </EventData>
</Event>

I have trouble understanding why an event with the TargetUserSid attribute of S-1-5-18 has been included in the view while it should not be. It works in the other direction too - if I define the filter to be *[EventData[Data[@Name='TargetUserSid'] and (Data='S-1-5-18')]], I see events with a different TargetUserSid "slipping through".

Chosing a different (long) SID from a domain object seems to work as expected and gives me a view with the events having TargetUserSid set accordingly only.

I also tried filtering on other attributes like TargetUserName, but only to encounter similar problems.

Any hints on how to fix my query or working examples of similar cases greatly appreciated.

windows-server-2008-r2

2 Answers

  1. Best Answer

    Try this: 

    <QueryList>
  <Query Id="0" Path="Security">
    <Select Path="Security">*[System[(EventID=4608)]]</Select>
    <Suppress Path="Security">*[EventData[Data[@Name="TargetUserSid"] = "S-1-5-18"]]</Suppress>
  </Query>
</QueryList>
    • 4

  2. I have observed the same on Windows 10 Desktop OS. A specific query like below, instead of giving specified events, results in all the process creation events. However, the same query works well in Server 2012 OS. 

     <QueryList>
 <Query Id="0" Path="Security">
   <Select Path="Security">
        *[EventData[Data[@Name='NewProcessName'] and (Data='C:\Windows\System32\process0.exe'  or Data='C:\Windows\System32\process1.exe' or Data='C:\Windows\process2.exe')]]
        and 
        *[System[(EventID=4688)]]
    </Select>
 </Query>
</QueryList>

    My workaround is to separate the search attribute values, something like this:

    <QueryList>
  <Query Id="0" Path="Security">
    <Select Path="Security">
        (*[EventData[Data[@Name='NewProcessName'] ='C:\Windows\System32\process0.exe']] 
         or
         *[EventData[Data[@Name='NewProcessName'] ='C:\Windows\process1.exe']]
         or
         *[EventData[Data[@Name='NewProcessName'] = 'C:\Windows\process2.exe']])
        and 
        *[System[(EventID=4688)]]
    </Select>
  </Query>
</QueryList>
    • 0