Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
302 detections
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Detects behavior where PowerShell or pwsh executes msiexec.exe to silently install an MSI file located in a temporary directory with a GUID-prefixed filename, optionally following a recent download from a remote URL.
Detects a sequence where PowerShell downloads an .msi installer file from Azure Blob Storage, followed closely by msiexec.exe spawning a PowerShell process on the same device.
MSI-backed loader execution chain
Cortex XDR
This query uses the process ID of each child to match the parent process's PID, then reconstructs the chain back to explorer.exe. It also checks for the encoded PowerShell, silent MSI installation, and embedded MSI execution behaviours described in the source article.
Important caveats
- Causality scope: This finds matching process events within a shared causality ID; it does not establish that each process directly launched the next.
- Explorer root: The root process may not share the same causality ID in every telemetry scenario. If this join removes otherwise valid results, investigate the root separately.
- Strict matching: Requiring every stage will miss partial chains and variants with different command-line arguments. Consider separate alerts for the encoded PowerShell and silent MSI behaviours.
- Validation: Confirm the field names, join syntax, and causality-ID population against your tenant before deploying this as a production detection.
Important caveats
- Causality scope: This finds matching process events within a shared causality ID; it does not establish that each process directly launched the next.
- Explorer root: The root process may not share the same causality ID in every telemetry scenario. If this join removes otherwise valid results, investigate the root separately.
- Strict matching: Requiring every stage will miss partial chains and variants with different command-line arguments. Consider separate alerts for the encoded PowerShell and silent MSI behaviours.
- Validation: Confirm the field names, join syntax, and causality-ID population against your tenant before deploying this as a production detection.
Detects a Python process spawning msiexec.exe followed by a high volume of LDAP connections (burst) from the same device within a 30-minute window, potentially indicating post-exploitation activity such as domain enumeration.
Detects MsiExec loading a DLL and calling its DllUnregisterServer function
The following analytic detects MSIExec making network connections over ports 443 or 80. This behavior is identified by correlating process creation events from Endpoint Detection and Response (EDR) agents with network traffic logs. Typically, MSIExec does not perform network communication to the internet, making this activity unusual and potentially indicative of malicious behavior. If confirmed malicious, an attacker could be using MSIExec to download or communicate with external servers, potentially leading to data exfiltration, command and control (C2) communication, or further malware deployment.
Detects msiexec.exe executing an MSI package named update_ms.msi
staged in ProgramData. Chaos ransomware disguises this installer's properties
and filename to impersonate a legitimate Windows Update package. On execution,
a custom action (CA_Run_EA2AEBC3) loads an embedded DLL (Bin_lib_EA2AEBC3,
lib.dll) directly into memory, deploying the msaRAT payload. This rule sees
the installer execution only; the in-memory module load is not observed here
and would need a separate PROCESS_MODULE_LOAD rule.
staged in ProgramData. Chaos ransomware disguises this installer's properties
and filename to impersonate a legitimate Windows Update package. On execution,
a custom action (CA_Run_EA2AEBC3) loads an embedded DLL (Bin_lib_EA2AEBC3,
lib.dll) directly into memory, deploying the msaRAT payload. This rule sees
the installer execution only; the in-memory module load is not observed here
and would need a separate PROCESS_MODULE_LOAD rule.
The following analytic detects the use of msiexec.exe with an HTTP or
HTTPS URL in the command line, indicating a remote file download attempt. This detection
leverages data from Endpoint Detection and Response (EDR) agents, focusing on process
execution logs that include command-line details. This activity is significant as
it may indicate an attempt to download and execute potentially malicious software
from a remote server. If confirmed malicious, this could lead to unauthorized code
execution, system compromise, or further malware deployment within the network.
HTTPS URL in the command line, indicating a remote file download attempt. This detection
leverages data from Endpoint Detection and Response (EDR) agents, focusing on process
execution logs that include command-line details. This activity is significant as
it may indicate an attempt to download and execute potentially malicious software
from a remote server. If confirmed malicious, this could lead to unauthorized code
execution, system compromise, or further malware deployment within the network.
The following analytic detects the execution of msiexec.exe with the /y switch parameter, which enables the loading of DLLRegisterServer. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process command-line arguments and parent-child process relationships. This activity is significant because it can indicate an attempt to register malicious DLLs, potentially leading to code execution or persistence on the system. If confirmed malicious, this could allow an attacker to execute arbitrary code, escalate privileges, or maintain persistence within the environment.
The following analytic detects the use of msiexec.exe with the /z switch parameter, which is used to unload DLLRegisterServer. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs, including command-line arguments. This activity is significant because unloading DLLRegisterServer can be indicative of an attempt to deregister a DLL, potentially disrupting legitimate services or hiding malicious activity. If confirmed malicious, this could allow an attacker to disable security controls, evade detection, or disrupt system functionality, leading to further compromise of the environment.
This rule detects a suspicious sequence of events where a process named RMM.Agent.exe executes a PowerShell command to download and install 'ClientSetup.msi' via msiexec.exe, followed closely by the execution of a ScreenConnect client process. This chain of activity is consistent with unauthorized or potentially malicious deployment of ScreenConnect (ConnectWise Control) for persistent remote access.
This rule detects a suspicious sequence of events where a process named RMM.Agent.exe executes a PowerShell command to download and install 'ClientSetup.msi' via msiexec.exe, followed closely by the execution of a ScreenConnect client process. This chain of activity is consistent with unauthorized or potentially malicious deployment of ScreenConnect (ConnectWise Control) for persistent remote access.
Detects a multi-stage infection chain associated with RedFlick, involving the delivery of VHDX files or PDF attachments. The rule correlates malicious activities such as SSH-based tool download (using PermitLocalCommand), PowerShell-based PDF decoding/extraction, PowerShell VHDX disk mounting, and silent MSI installation from remote URLs. It monitors for these activities within user-writable directories like Downloads or Temp.
Detects execution of AgtaBackupAgent.msi via command-line tools such as PowerShell or msiexec.exe. This activity is monitored as it may indicate an attempt to install backup software or potential malicious masquerading using the MSI installer, particularly when using silent flags or accessing from temp directories.
Detects execution of AgtaBackupAgent.msi via command-line tools such as PowerShell or msiexec.exe. This activity is monitored as it may indicate an attempt to install backup software or potential malicious masquerading using the MSI installer, particularly when using silent flags or accessing from temp directories.
Detects msiexec.exe spawned from explorer.exe, consistent with a user double-clicking a malicious .lnk shortcut, where the command line triggers the installation of an MSI package hosted on a remote HTTP/HTTPS server. This behavior is a known initial access technique used by FIN7 to deliver malicious payloads.
Detects the execution of msiexec.exe where the process image is located in the user's local AppData directory under specific suspicious folder names. This behavior is indicative of a user-land installer or potential malware attempting to maintain persistence or execute malicious packages while masquerading as common applications.
Detects the Windows Installer service (msiexec.exe) being launched by known remote access software processes like msra.exe (Microsoft Remote Assistance) or anydesk.exe. This behavior is often associated with unauthorized software installation or payload delivery via remote support tools.
Detects the 'ClickFix' social engineering pattern where an adversary tricks a user into using the Windows Run dialog (explorer.exe) to execute msiexec.exe, downloading and installing a remote MSI package. This is frequently associated with malware delivery, such as Psychedelic Stealer, where users are prompted to copy and paste malicious commands under the guise of fake error messages or CAPTCHAs.
Detects msiexec.exe initiating network connections to or executing packages from endpoints containing 'capher.php' and token parameters. This behavior is associated with the 'ClickFix' delivery chain, where adversaries use malicious websites or scripts to trick users into downloading and executing installer files.
Detects instances where a legitimate Remote Monitoring and Management (RMM) agent (MSP360 or Faronics) is used to execute PowerShell commands that silently install ScreenConnect (ConnectWise Control) MSI packages within a 10-minute window. This behavior is indicative of an adversary abusing administrative tools for lateral movement or persistence.
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