DFIRHub

Windows event log ยท Microsoft-Windows-TerminalServices-RDPClient/Operational1029 RDP (outgoing connection)

CyberChef recipes to calculate the same encoded value from a known username

  • Remote access
  • 2 fields
  • Microsoft-Windows-TerminalServices-RDPClient%4Operational.evtx
  • Microsoft-Windows-TerminalServices-ClientActiveXCore

Notes

  • CyberChef recipes to calculate the same encoded value from a known username
  • OS : Windows 7 / Windows Server 2008 R2
  • Hash : Base64(SHA1(UserName))
  • Example:
  • Input = administrator
  • Output = /6UN2Oco6V2sEKuooAIuzrrOUrk=
  • OS : Windows 10
  • Hash : Base64(SHA256(UserName))
  • Output = WAlZ81aqzLQmoWEfQivmPQwJxIm/XQcDjplQdjznr5E=
  • If you need to decode a large number of encoded values, try my recipe for CyberChef. These are the steps to follow:
  • 1) Copy and paste the following recipe into CyberChef:
  • Compact JSON:
  • [{"op":"Unique","args":["Line feed"]},{"op":"Fork","args":["\\n","\\n",false]},{"op":"Find / Replace","args":[{"option":"Regex","string":"-\\\\-"},"",true,false,true,false]},{"op":"Find / Replace","args":[{"option":"Regex","string":"(User Name|Payload Data.|Target: |Target \\(encoded\\).*| \\(S\\-.*\\)|NETWORK SERVICE)"},"",true,false,true,false]},{"op":"Find / Replace","args":[{"option":"Regex","string":"(^.*\\\\|S-[0-9\\-]*)"},"",true,false,true,false]},{"op":"Register","args":["([\\s\\S]*)",true,false,false]},{"op":"Decode text","args":["UTF-8 (65001)"]},{"op":"Encode text","args":["UTF-16LE (1200)"]},{"op":"SHA1","args":[],"disabled":true},{"op":"SHA2","args":["256"]},{"op":"From Hex","args":["Space"]},{"op":"To Base64","args":["A-Za-z0-9+/="]},{"op":"Register","args":["([\\s\\S]*)",true,false,false]},{"op":"Find / Replace","args":[{"option":"Simple string","string":"$R1"},"$R1,$R0",true,false,true,false]},{"op":"Merge","args":[]},{"op":"Unique","args":["Line feed"]},{"op":"Sort","args":["Line feed",false,"Alphabetical (case insensitive)"]},{"op":"To Table","args":[",","\\r\\n",false,"HTML"]}]
  • 2) From CyberChef, disable or remove the hash operation (SHA1 or SHA2) that you don't need
  • 3) From Timeline Explorer:
  • - Column "User Name" : copy all the non-blank values
  • - Column "Payload Data1": copy all the values containing "Target:"
  • 4) Paste what you just copied into the input area of CyberChef (no need to clean or dedupe the input before pasting)
  • 5) Bake!
  • Articles:

Fields EvtxECmd extracts

2 columns in the EvtxECmd CSV

  • PayloadData1Target (encoded): %Base64RDPUserNameHash%
    • %Base64RDPUserNameHash% = /Event/EventData/Data[@Name="TraceMessage"]
  • PayloadData6ActivityID: %ActivityID%
    • %ActivityID% = /Event/System/Correlation/@ActivityID

Sample event

Event XML from the map file

<Event>
  <System>
    <Provider Name="Microsoft-Windows-TerminalServices-ClientActiveXCore" Guid="28aa95bb-d444-4719-a36f-40462168127e"/>
    <EventID>1029</EventID>
    <Version>0</Version>
    <Level>4</Level>
    <Task>101</Task>
    <Opcode>10</Opcode>
    <Keywords>0x4000000000000000</Keywords>
    <TimeCreated SystemTime="2020-11-28 10:17:20.4692527"/>
    <EventRecordID>7</EventRecordID>
    <Correlation ActivityID="cd839c41-3564-4fb9-afdd-e4b3abba0000"/>
    <Execution ProcessID="2988" ThreadID="1068"/>
    <Channel>Microsoft-Windows-TerminalServices-RDPClient/Operational</Channel>
    <Computer>IEWIN7</Computer>
    <Security UserID="S-1-5-21-3583694148-1414552638-2922671848-1000"/>
  </System>
  <EventData>
    <Data Name="TraceMessage">q2iIC1HjphTQfGcYqIwX0kR5WjQ=-</Data>
  </EventData>
</Event>

References

6 links

Source: evtx/Maps/Microsoft-Windows-TerminalServices-RDPClient-Operational_Microsoft-Windows-TerminalServices-ClientActiveXCore_1029.map(opens in new tab) by Gabriele Zambelli @gazambelli and contributors(opens in new tab), MIT License(opens in new tab)