Elastic medium stable eql

MsiExec Service Child Process With Network Connection

Identifies the execution of an MsiExec service child process followed by network or dns lookup activity. Adversaries may abuse Windows Installers for initial access and delivery of malware.

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Detection Logic

sequence by process.entity_id with maxspan=1m
 [process where host.os.type == "windows" and event.type : "start" and
  process.parent.name : "msiexec.exe" and process.parent.args : "/v" and
  not process.executable :
        ("?:\\Windows\\System32\\msiexec.exe",
         "?:\\Windows\\sysWOW64\\msiexec.exe",
         "?:\\Windows\\system32\\srtasks.exe",
         "?:\\Windows\\syswow64\\srtasks.exe",
         "?:\\Windows\\sys*\\taskkill.exe",
         "?:\\Program Files\\*.exe",
         "?:\\Program Files (x86)\\*.exe",
         "?:\\Windows\\Installer\\MSI*.tmp",
         "?:\\Windows\\Microsoft.NET\\Framework*\\RegSvcs.exe",
         "C:\\Windows\\System32\\regsvr32.exe",
         "C:\\Windows\\Sys?????\\certutil.exe",
         "C:\\Windows\\System32\\WerFault.exe",
         "C:\\Windows\\System32\\wevtutil.exe",
         "C:\\Windows\\SysWOW64\\WindowsPowerShell\\v1.0\\powershell.exe") and
 not (process.name : ("rundll32.exe", "regsvr32.exe", "powershell.exe", "regasm.exe", "wscript.exe") and process.args : ("?:\\Program Files\\*", "?:\\Program Files (x86)\\*")) and
 not (?process.code_signature.subject_name : ("Bruno Software Inc", "Proton AG", "Axis Communications AB", "Citrix Systems, Inc.", "NSUS Limited", "Action1 Corporation", "Solarwinds Worldwide, LLC") and
      ?process.code_signature.trusted == true) and
 not (?process.pe.original_file_name in ("dxsetup.exe", "MofCompiler.exe", "ShellApp.exe") and
      ?process.code_signature.subject_name : "Microsoft Corporation" and ?process.code_signature.trusted == true) and
 not ?process.hash.sha256 in ("cfaef8c711db04d6c4a4381c66ac21b9e234e57febedb77fedc9316898b214bc",
                              "2f26f37cce780ca76f0dbac0de233f4c8d84c31b3f37380b9d5faacc3ee2d03e",
                              "7d9c691bfbf3beb78919dfd940fa6d325c3437425d5b0371df39aef6accf858d")
 ]
[network where host.os.type == "windows" and process.name != null and
 not dns.question.name : ("core.bdec.microsoft.com", "go.microsoft.com", "ocsp.digicert.com", "localhost", "www.google-analytics.com",
                          "ocsp.verisign.com", "*.symcb.com")]

Field Validations

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