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P4T12ICK
78 lines
2.7 KiB
YAML
78 lines
2.7 KiB
YAML
name: Winhlp32 Spawning a Process
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id: d17dae9e-2618-11ec-b9f5-acde48001122
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version: 1
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date: '2021-10-05'
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author: Michael Haag, Splunk
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status: production
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type: TTP
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description: The following analytic identifies winhlp32.exe, found natively in `c:\windows\`,
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spawning a child process that loads a file out of appdata, programdata, or temp.
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Winhlp32.exe has a rocky past in that multiple vulnerabilities were found and added
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to MetaSploit. WinHlp32.exe is required to display 32-bit Help files that have the
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".hlp" file name extension. This particular instance is related to a Remcos sample
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where dynwrapx.dll is added to the registry under inprocserver32, and later module
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loaded by winhlp32.exe to spawn wscript.exe and load a vbs or file from disk. During
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triage, review parallel processes to identify further suspicious behavior. Review
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module loads for unsuspecting unsigned modules. Capture any file modifications and
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analyze.
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data_source:
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- Sysmon Event ID 1
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search:
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selection1:
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CommandLine:
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- '*\\appdata\\*'
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- '*\\programdata\\*'
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- '*\\temp\\*'
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ParentImage: winhlp32.exe
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condition: selection1
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how_to_implement: To successfully implement this search you need to be ingesting information
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on process that include the name of the process responsible for the changes from
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your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
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confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
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endpoint product.
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known_false_positives: False positives should be limited as winhlp32.exe is typically
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not used with the latest flavors of Windows OS. However, filter as needed.
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references:
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- https://www.exploit-db.com/exploits/16541
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- https://tria.ge/210929-ap75vsddan
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- https://www.virustotal.com/gui/file/cb77b93150cb0f7fe65ce8a7e2a5781e727419451355a7736db84109fa215a89
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tags:
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analytic_story:
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- Remcos
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asset_type: Endpoint
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confidence: 100
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impact: 80
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message: An instance of $parent_process_name$ spawning $process_name$ was identified
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on endpoint $dest$, and is not typical activity for this process.
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mitre_attack_id:
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- T1055
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observable:
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- name: user
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type: User
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role:
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- Victim
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- name: dest
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type: Hostname
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role:
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- Victim
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- name: parent_process_name
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type: Process
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role:
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- Parent Process
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- name: process_name
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type: Process
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role:
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- Child Process
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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risk_score: 80
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security_domain: endpoint
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tests:
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- name: True Positive Test
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attack_data:
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- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/remcos/remcos/windows-sysmon.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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