Detect Mavinject in Elastic Security
Adversaries may abuse mavinject.exe to proxy execution of malicious code. Mavinject.exe is the Microsoft Application Virtualization Injector, a Windows utility that can inject code into external processes as part of Microsoft Application Virtualization (App-V). Adversaries abuse it to inject malicious DLLs into running processes (DLL injection) using the /INJECTRUNNING flag. Since mavinject.exe is a signed Microsoft binary, it can bypass application control. TONESHELL malware has been observed using mavinject.exe for process injection.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1218 System Binary Proxy Execution
- Sub-technique
- T1218.013 Mavinject
- Canonical reference
- https://attack.mitre.org/techniques/T1218/013/
Elastic Detection Query
process where event.type == "start" and process.name : "mavinject.exe" and (
process.args : "/INJECTRUNNING" or
process.args : "/INJECTRUNNING*" or
process.command_line : "*mavinject*"
)
| eval inject_running = if(process.args like "/INJECTRUNNING*", 1, 0)
| eval suspicious_path = if(process.command_line like "*Temp*" or process.command_line like "*AppData*" or process.command_line like "*Downloads*" or process.command_line like "*Public*" or process.command_line like "*Desktop*", 1, 0)
| eval suspicious_parent = if(process.parent.name in ("cmd.exe", "powershell.exe", "wscript.exe", "cscript.exe", "mshta.exe", "winword.exe", "excel.exe"), 1, 0)Detects mavinject.exe process creation with /INJECTRUNNING flag, suspicious DLL paths, or suspicious parent processes. Covers DLL injection abuse of the Microsoft Application Virtualization Injector as described in T1218.013.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate Microsoft App-V deployments where administrators use mavinject.exe to inject approved virtualization components into running processes
- Automated software testing pipelines that use mavinject.exe to instrument processes for coverage or debugging purposes
- Application compatibility tooling in enterprise environments that invokes mavinject.exe as part of sanctioned compatibility shims
Other platforms for T1218.013
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 1Mavinject DLL Injection into Running Process
Expected signal: Sysmon Event ID 1: mavinject.exe with /INJECTRUNNING and a PID in command line. Sysmon Event ID 8 (CreateRemoteThread) from notepad.exe. Sysmon Event ID 7 (Image Load) on notepad.exe for the injected DLL. Security Event ID 4688.
- Test 2Mavinject from PowerShell Parent
Expected signal: Sysmon Event ID 1: powershell.exe then mavinject.exe with ParentImage=powershell.exe and /INJECTRUNNING in command line. SuspiciousParent and InjectRunning both fire.
- Test 3Mavinject with DLL from Temp Directory
Expected signal: Sysmon Event ID 11: DLL written to Temp. Sysmon Event ID 1: mavinject.exe with /INJECTRUNNING and Temp path. The injection will fail (PID 4 is SYSTEM) but the process creation and file creation events fire.
References (4)
- https://attack.mitre.org/techniques/T1218/013/
- https://lolbas-project.github.io/lolbas/Binaries/Mavinject/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.013/T1218.013.md
- https://www.trendmicro.com/en_us/research/25/b/earth-preta-campaign-uses-ppam-files-and-encrypted-payloads-to-evade-detection.html
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