Detect Msiexec in Splunk
Adversaries may abuse msiexec.exe to proxy execution of malicious payloads. Msiexec.exe is the command-line utility for the Windows Installer and is commonly associated with executing installation packages (.msi). Since it is a signed Microsoft binary, msiexec.exe can bypass application control solutions. Adversaries use it to launch local or remote MSI files and to execute DLLs. Execution may also be elevated to SYSTEM if the AlwaysInstallElevated policy is enabled. Widely abused by malware families including QakBot, IcedID, Emotet, Clop, Maze, Ragnar Locker, Latrodectus, Raspberry Robin, TA505, Rancor, ZIRCONIUM, and many others.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1218 System Binary Proxy Execution
- Sub-technique
- T1218.007 Msiexec
- Canonical reference
- https://attack.mitre.org/techniques/T1218/007/
SPL Detection Query
index=wineventlog sourcetype="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" EventCode=1
Image="*\\msiexec.exe"
| eval RemoteMSI=if(match(CommandLine, "http[s]?://|ftp://"), 1, 0)
| eval DLLExec=if(match(CommandLine, "/y "), 1, 0)
| eval SilentInstall=if(match(CommandLine, "(/q|/quiet|/passive)"), 1, 0)
| eval SuspiciousPath=if(match(CommandLine, "(Temp|AppData|Downloads|Public|Desktop)"), 1, 0)
| eval SuspiciousParent=if(match(ParentImage, "(cmd|powershell|wscript|cscript|mshta|winword|excel|outlook)\.exe"), 1, 0)
| eval PropertyPair=if(match(CommandLine, "[A-Z]+=[a-zA-Z0-9+/]{10,}"), 1, 0)
| eval RiskScore=RemoteMSI + DLLExec + (SilentInstall * SuspiciousPath) + SuspiciousParent + PropertyPair
| where RiskScore > 0
| table _time, host, User, CommandLine, ParentImage, ParentCommandLine, RemoteMSI, DLLExec, SilentInstall, SuspiciousPath, SuspiciousParent, PropertyPair, RiskScore
| sort - _timeDetects msiexec.exe abuse using Sysmon Event ID 1. Scores across multiple risk indicators with contextual weighting — silent install is only scored when combined with a suspicious path, reducing false positives from legitimate software deployment. DLL execution (/y flag) and remote MSI loading score regardless of path.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Legitimate software deployment via SCCM, Intune, or PDQ Deploy which frequently calls msiexec.exe with /quiet or /passive flags
- System updates and Windows Update installation processes that use msiexec.exe with silent flags
- IT administrators manually installing software packages with administrative flags
- Software auto-update mechanisms that download and install MSI packages remotely
Other platforms for T1218.007
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Msiexec Remote MSI Execution
Expected signal: Sysmon Event ID 1: msiexec.exe with URL and /q flag. Sysmon Event ID 3: Network connection attempt to 127.0.0.1:8080. Security Event ID 4688. The installation will fail (no server) but the process creation event fires.
- Test 2Msiexec DLL Execution via /y Flag
Expected signal: Sysmon Event ID 11: DLL written to Temp. Sysmon Event ID 1: msiexec.exe with /y flag and Temp path. Sysmon Event ID 7 (Image Load) for the DLL being loaded by msiexec.
- Test 3Msiexec Silent Install from Temp Directory via PowerShell
Expected signal: Sysmon Event ID 1: powershell.exe, then msiexec.exe with /q and Temp path, ParentImage=powershell.exe. Both SuspiciousParent and SuspiciousPath fire. Security Event ID 4688 for both.
References (6)
- https://attack.mitre.org/techniques/T1218/007/
- https://lolbas-project.github.io/lolbas/Binaries/Msiexec/
- https://blog.trendmicro.com/trendlabs-security-intelligence/attack-using-windows-installer-msiexec-exe-leads-lokibot/
- https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/msiexec
- https://docs.microsoft.com/en-us/windows/win32/msi/alwaysinstallelevated
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.007/T1218.007.md
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