Common Windows process launched from unusual path

Rule ID

PH_Rule_OSQ_WIN_4

Default Status

Enabled

Description

Detects common windows processes not running from their well-known path. Processes checked are: Console Windows Host process (Conhost.exe), Client Server Runtime Subsystem (csrss.exe), File explorer (explorer.exe), Dllhost.exe, Local Security Authority Subsystem Service (lssass.exe), Service Control Manager Service (services.exe), Session Manager Subsystem (smss.exe), Shared Service Process (svchost.exe), Windows startup initialization process (wininit.exe), Logon/logoff Management service (winlogon.exe), WMI Provider service (wmiprvse.exe)

Severity

MITRE ATT&CK® Tactics

Persistence

Persistence consists of techniques that adversaries use to keep access to systems across restarts, changed credentials, and other interruptions that could cut off their access. Techniques used for persistence include any access, action, or configuration changes that let them maintain their foothold on systems, such as replacing or hijacking legitimate code or adding startup code.

https://attack.mitre.org/tactics/TA0003

MITRE ATT&CK® Techniques

T1037.001

Boot or Logon Initialization Scripts: Logon Script (Windows)

Adversaries may use Windows logon scripts automatically executed at logon initialization to establish persistence. Windows allows logon scripts to be run whenever a specific user or group of users log into a system.

https://attack.mitre.org/techniques/T1037/001

Impacts

Server

Data Source

The following Windows osqueries via FortiSIEM Agent: windows_conhost.exe_incorrect_path, windows_csrss.exe_incorrect_path, windows_explorer.exe_incorrect_path, windows_dllhost.exe_incorrect_path, Windows_lsass.exe_incorrect_path, Windows_services.exe_incorrect_path, Windows_smss.exe_incorrect_path, Windows_svchost.exe_incorrect_path, Windows_wininit.exe_incorrect_path, Windows_winlogon.exe_incorrect_path, Windows_wmiprvse.exe_incorrect_path

Detection

Correlation

Remediation Guidance

No remediation guidance specified

Time Window

If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.

300 seconds

Trigger Conditions

If the following defined pattern/s occur within a 300 second time window.

Filter

SubPattern Definitions

SubPattern Name: Filter

This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.

SubPattern Query

This is the query logic that matches incoming events

eventType IN ("PH_OSQUERY_WIN_CONHOST_BAD_PATH", "PH_OSQUERY_WIN_CSRSS_BAD_PATH", "PH_OSQUERY_WIN_EXPLORER_BAD_PATH", "PH_OSQUERY_WIN_DLLHOST_BAD_PATH", "PH_OSQUERY_WIN_LSASS_BAD_PATH", "PH_OSQUERY_WIN_SERVICES_BAD_PATH", "PH_OSQUERY_WIN_SMSS_BAD_PATH", "PH_OSQUERY_WIN_SVCHOST_BAD_PATH", "PH_OSQUERY_WIN_WININIT_BAD_PATH", "PH_OSQUERY_WIN_WINLOGIN_BAD_PATH", "PH_OSQUERY_WIN_WMIPRVSE_BAD_PATH") AND totalNum >= 1

Group by Attributes

This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID

reptDevName,procName,filePath

Aggregate Constraint

This is most typically a numerical constraint that defines when the rule should trigger an incident

COUNT(*) >= 1

Incident Attribute Mapping

This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.

The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern

 hostName = Filter.reptDevName,
 procName = Filter.procName,
 filePath = Filter.filePath

FortiSIEM Rules