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Proc creation lnx webshell detection #5128

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CheraghiMilad
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@CheraghiMilad CheraghiMilad commented Dec 13, 2024 •
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Summary of the Pull Request

Some images added.

Changelog

Example Log Event

groups log

<Event>
  <System>
    <Provider Name="Linux-Sysmon" Guid="{ff032593-a8d3-4f13-b0d6-01fc615a0f97}"/>
    <EventID>1</EventID>
    <Version>5</Version>
    <Level>4</Level>
    <Task>1</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2024-12-01T11:07:26.551148000Z"/>
    <EventRecordID>286262</EventRecordID>
    <Correlation/>
    <Execution ProcessID="1258" ThreadID="1258"/>
    <Channel>Linux-Sysmon/Operational</Channel>
    <Computer>caldera-virtual-machine</Computer>
    <Security UserId="0"/>
  </System>
  <EventData>
    <Data Name="RuleName">-</Data>
    <Data Name="UtcTime">2024-11-26 18:50:45.939</Data>
    <Data Name="ProcessGuid">{36fe7a82-1885-6746-91ce-8c4be7550000}</Data>
    <Data Name="ProcessId">19678</Data>
    <Data Name="Image">/usr/bin/groups</Data>
    <Data Name="FileVersion">-</Data>
    <Data Name="Description">-</Data>
    <Data Name="Product">-</Data>
    <Data Name="Company">-</Data>
    <Data Name="OriginalFileName">-</Data>
    <Data Name="CommandLine">groups</Data>
    <Data Name="CurrentDirectory">/tmp</Data>
    <Data Name="User">caldera</Data>
    <Data Name="LogonGuid">{36fe7a82-0000-0000-e803-000000000000}</Data>
    <Data Name="LogonId">1000</Data>
    <Data Name="TerminalSessionId">3</Data>
    <Data Name="IntegrityLevel">no level</Data>
    <Data Name="Hashes">SHA256=175a52497e658e138f7dce3fbb3ba7d794f302dc7be29f9c9ca79a8cb377554c</Data>
    <Data Name="ParentProcessGuid">{36fe7a82-1381-6743-d526-4b5458550000}</Data>
    <Data Name="ParentProcessId">2249</Data>
    <Data Name="ParentImage">/usr/bin/bash</Data>
    <Data Name="ParentCommandLine">bash</Data>
    <Data Name="ParentUser">caldera</Data>
  </EventData>
</Event>

netstat log

<Event>
  <System>
    <Provider Name="Linux-Sysmon" Guid="{ff032593-a8d3-4f13-b0d6-01fc615a0f97}"/>
    <EventID>1</EventID>
    <Version>5</Version>
    <Level>4</Level>
    <Task>1</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2024-12-01T11:08:55.895691000Z"/>
    <EventRecordID>286269</EventRecordID>
    <Correlation/>
    <Execution ProcessID="1258" ThreadID="1258"/>
    <Channel>Linux-Sysmon/Operational</Channel>
    <Computer>caldera-virtual-machine</Computer>
    <Security UserId="0"/>
  </System>
  <EventData>
    <Data Name="RuleName">-</Data>
    <Data Name="UtcTime">2024-11-26 18:52:15.275</Data>
    <Data Name="ProcessGuid">{36fe7a82-18df-6746-7d0c-f4aabf550000}</Data>
    <Data Name="ProcessId">19688</Data>
    <Data Name="Image">/usr/bin/netstat</Data>
    <Data Name="FileVersion">-</Data>
    <Data Name="Description">-</Data>
    <Data Name="Product">-</Data>
    <Data Name="Company">-</Data>
    <Data Name="OriginalFileName">-</Data>
    <Data Name="CommandLine">netstat localgroup</Data>
    <Data Name="CurrentDirectory">/tmp</Data>
    <Data Name="User">caldera</Data>
    <Data Name="LogonGuid">{36fe7a82-0000-0000-e803-000000000000}</Data>
    <Data Name="LogonId">1000</Data>
    <Data Name="TerminalSessionId">3</Data>
    <Data Name="IntegrityLevel">no level</Data>
    <Data Name="Hashes">SHA256=7af5f6cda055b65e31298fe20ed4456a87d2ca92803552bc0d3422f0e1a1fda1</Data>
    <Data Name="ParentProcessGuid">{36fe7a82-1381-6743-d526-4b5458550000}</Data>
    <Data Name="ParentProcessId">2249</Data>
    <Data Name="ParentImage">/usr/bin/bash</Data>
    <Data Name="ParentCommandLine">bash</Data>
    <Data Name="ParentUser">caldera</Data>
  </EventData>
</Event>

getent log

Dec 1 12:08:30 caldera-virtual-machine sysmon: 
<Event>
  <System>
    <Provider Name="Linux-Sysmon" Guid="{ff032593-a8d3-4f13-b0d6-01fc615a0f97}"/>
    <EventID>1</EventID>
    <Version>5</Version>
    <Level>4</Level>
    <Task>1</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2024-12-01T11:08:30.797177000Z"/>
    <EventRecordID>286268</EventRecordID>
    <Correlation/>
    <Execution ProcessID="1258" ThreadID="1258"/>
    <Channel>Linux-Sysmon/Operational</Channel>
    <Computer>caldera-virtual-machine</Computer>
    <Security UserId="0"/>
  </System>
  <EventData>
    <Data Name="RuleName">-</Data>
    <Data Name="UtcTime">2024-11-26 18:51:50.183</Data>
    <Data Name="ProcessGuid">{36fe7a82-18c6-6746-6570-640d07560000}</Data>
    <Data Name="ProcessId">19682</Data>
    <Data Name="Image">/usr/bin/getent</Data>
    <Data Name="FileVersion">-</Data>
    <Data Name="Description">-</Data>
    <Data Name="Product">-</Data>
    <Data Name="Company">-</Data>
    <Data Name="OriginalFileName">-</Data>
    <Data Name="CommandLine">getent group</Data>
    <Data Name="CurrentDirectory">/tmp</Data>
    <Data Name="User">caldera</Data>
    <Data Name="LogonGuid">{36fe7a82-0000-0000-e803-000000000000}</Data>
    <Data Name="LogonId">1000</Data>
    <Data Name="TerminalSessionId">3</Data>
    <Data Name="IntegrityLevel">no level</Data>
    <Data Name="Hashes">SHA256=b8c45799a591949d1728e7177fa14ddb110102dfe20d7b3610ce7f448e7bb902</Data>
    <Data Name="ParentProcessGuid">{36fe7a82-1381-6743-d526-4b5458550000}</Data>
    <Data Name="ParentProcessId">2249</Data>
    <Data Name="ParentImage">/usr/bin/bash</Data>
    <Data Name="ParentCommandLine">bash</Data>
    <Data Name="ParentUser">caldera</Data>
    host = caldera-virtual-machine
    source = Syslog:Linux-Sysmon/Operational
    sourcetype = sysmon_linux
  </EventData>
</Event>

id -Gn log

<Event>
  <System>
    <Provider Name="Linux-Sysmon" Guid="{ff032593-a8d3-4f13-b0d6-01fc615a0f97}"/>
    <EventID>1</EventID>
    <Version>5</Version>
    <Level>4</Level>
    <Task>1</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2024-12-09T07:17:20.100898000Z"/>
    <EventRecordID>375686</EventRecordID>
    <Correlation/>
    <Execution ProcessID="1252" ThreadID="1252"/>
    <Channel>Linux-Sysmon/Operational</Channel>
    <Computer>caldera-virtual-machine</Computer>
    <Security UserId="0"/>
  </System>
  <EventData>
    <Data Name="RuleName">-</Data>
    <Data Name="UtcTime">2024-12-08 17:03:58.251</Data>
    <Data Name="ProcessGuid">{36fe7a82-d17e-6755-e121-65502e560000}</Data>
    <Data Name="ProcessId">5294</Data>
    <Data Name="Image">/usr/bin/id</Data>
    <Data Name="FileVersion">-</Data>
    <Data Name="Description">-</Data>
    <Data Name="Product">-</Data>
    <Data Name="Company">-</Data>
    <Data Name="OriginalFileName">-</Data>
    <Data Name="CommandLine">id -Gn caldera</Data>
    <Data Name="CurrentDirectory">/home/caldera</Data>
    <Data Name="User">caldera</Data>
    <Data Name="LogonGuid">{36fe7a82-0000-0000-e803-000000000000}</Data>
    <Data Name="LogonId">1000</Data>
    <Data Name="TerminalSessionId">3</Data>
    <Data Name="IntegrityLevel">no level</Data>
    <Data Name="Hashes">SHA256=371021b0c9ab1a3c893ca98b1c648445e3cfe5c6883d9c0a5b1d0339c0d4cd2d</Data>
    <Data Name="ParentProcessGuid">{36fe7a82-6868-6755-d5d6-c908e8550000}</Data>
    <Data Name="ParentProcessId">2352</Data>
    <Data Name="ParentImage">/usr/bin/bash</Data>
    <Data Name="ParentCommandLine">bash</Data>
    <Data Name="ParentUser">caldera</Data>
  </EventData>
</Event>

Fixed Issues

SigmaHQ Rule Creation Conventions

  • If your PR adds new rules, please consider following and applying these conventions

@github-actions github-actions bot added Rules Linux Pull request add/update linux related rules labels Dec 13, 2024
nasbench
nasbench reviewed Dec 14, 2024
View reviewed changes
rules-threat-hunting/linux/process_creation/proc_creation_lnx_susp_local_groups_discovery.yml
Comment on lines +39 to +41
selection_4:
Image|endswith: '/netstat'
CommandLine|contains: 'localgroup'
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@nasbench nasbench Dec 14, 2024 •
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Please provide logs related to the netstat selection with screenshots of expected output.

@nasbench
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@CheraghiMilad you have to fill the template or this PR will get closed.

As it is stated the changelog and information is mandatory

@nasbench nasbench added the Author Input Required changes the require information from original author of the rules label Dec 14, 2024
This was referenced Dec 14, 2024
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@CheraghiMilad @nasbench