LoFP / false positives are possible if legitimate applications are allowed to register tasks that call a shell to be spawned. filter as needed based on command-line or processes that are used legitimately.

• T1053.005

Sample rules

Windows Scheduled Task with Suspicious Name

• source: splunk
• technicques:
  • T1053.005

Description

The following analytic detects the creation, modification, or enabling of scheduled tasks with known suspicious or malicious task names. It leverages Windows Security EventCode 4698, 4700, and 4702 to identify when such tasks are registered, modified, or enabled. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.

Detection logic

`wineventlog_security` EventCode IN (4698,4700,4702)

| eval TaskContent = case(isnotnull(TaskContentNew),TaskContentNew,true(),TaskContent)

| xmlkv TaskContent

| stats count min(_time) as firstTime max(_time) as lastTime latest(Arguments) as Arguments latest(Author) as Author by Computer, TaskName, Command, Enabled, Hidden,Caller_User_Name, EventCode

| lookup windows_suspicious_tasks task_name as TaskName 

| where isnotnull(tool_type)

| eval command=TaskName, process=Command+if(isnotnull(Arguments)," ".Arguments,""), src_user=Author, user = Caller_User_Name, dest = Computer

| `security_content_ctime(firstTime)` 

| `security_content_ctime(lastTime)`

| `windows_scheduled_task_with_suspicious_name_filter`

WinEvent Scheduled Task Created to Spawn Shell

• source: splunk
• technicques:
  • T1053.005

Description

The following analytic detects the creation of scheduled tasks designed to execute commands using native Windows shells like PowerShell, Cmd, Wscript, or Cscript. It leverages Windows Security EventCode 4698 to identify when such tasks are registered. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.

Detection logic

`wineventlog_security` EventCode=4698 TaskContent IN ("*powershell.exe*", "*wscript.exe*", "*cscript.exe*", "*cmd.exe*", "*sh.exe*", "*ksh.exe*", "*zsh.exe*", "*bash.exe*", "*scrcons.exe*", "*pwsh.exe*") 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer, TaskName, TaskContent 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `winevent_scheduled_task_created_to_spawn_shell_filter`

WinEvent Scheduled Task Created Within Public Path

• source: splunk
• technicques:
  • T1053.005

Description

The following analytic detects the creation of scheduled tasks within user-writable paths using Windows Security EventCode 4698. It identifies tasks registered via schtasks.exe or TaskService that execute commands from directories like Public, ProgramData, Temp, and AppData. This behavior is significant as it may indicate an attempt to establish persistence or execute unauthorized commands. If confirmed malicious, an attacker could maintain long-term access, escalate privileges, or execute arbitrary code, posing a severe threat to system integrity and security.

Detection logic

`wineventlog_security` EventCode=4698 TaskContent IN ("*\\users\\public\\*", "*\\programdata\\*", "*\\temp\\*", "*\\Windows\\Tasks\\*", "*\\appdata\\*", "*\\perflogs\\*") 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer, TaskName, TaskContent 
|  rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `winevent_scheduled_task_created_within_public_path_filter`

• T1053.005

Sample rules

Windows Scheduled Task with Suspicious Name

• source: splunk
• technicques:
  • T1053.005

Description

The following analytic detects the creation, modification, or enabling of scheduled tasks with known suspicious or malicious task names. It leverages Windows Security EventCode 4698, 4700, and 4702 to identify when such tasks are registered, modified, or enabled. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.

Detection logic

`wineventlog_security` EventCode IN (4698,4700,4702)

| eval TaskContent = case(isnotnull(TaskContentNew),TaskContentNew,true(),TaskContent)

| xmlkv TaskContent

| stats count min(_time) as firstTime max(_time) as lastTime latest(Arguments) as Arguments latest(Author) as Author by Computer, TaskName, Command, Enabled, Hidden,Caller_User_Name, EventCode

| lookup windows_suspicious_tasks task_name as TaskName 

| where isnotnull(tool_type)

| eval command=TaskName, process=Command+if(isnotnull(Arguments)," ".Arguments,""), src_user=Author, user = Caller_User_Name, dest = Computer

| `security_content_ctime(firstTime)` 

| `security_content_ctime(lastTime)`

| `windows_scheduled_task_with_suspicious_name_filter`

WinEvent Scheduled Task Created to Spawn Shell

• source: splunk
• technicques:
  • T1053.005

Description

The following analytic detects the creation of scheduled tasks designed to execute commands using native Windows shells like PowerShell, Cmd, Wscript, or Cscript. It leverages Windows Security EventCode 4698 to identify when such tasks are registered. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.

Detection logic

`wineventlog_security` EventCode=4698 TaskContent IN ("*powershell.exe*", "*wscript.exe*", "*cscript.exe*", "*cmd.exe*", "*sh.exe*", "*ksh.exe*", "*zsh.exe*", "*bash.exe*", "*scrcons.exe*", "*pwsh.exe*") 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer, TaskName, TaskContent 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `winevent_scheduled_task_created_to_spawn_shell_filter`

WinEvent Scheduled Task Created Within Public Path

• source: splunk
• technicques:
  • T1053.005

Description

The following analytic detects the creation of scheduled tasks within user-writable paths using Windows Security EventCode 4698. It identifies tasks registered via schtasks.exe or TaskService that execute commands from directories like Public, ProgramData, Temp, and AppData. This behavior is significant as it may indicate an attempt to establish persistence or execute unauthorized commands. If confirmed malicious, an attacker could maintain long-term access, escalate privileges, or execute arbitrary code, posing a severe threat to system integrity and security.

Detection logic

`wineventlog_security` EventCode=4698 TaskContent IN ("*\\users\\public\\*", "*\\programdata\\*", "*\\temp\\*", "*\\Windows\\Tasks\\*", "*\\appdata\\*", "*\\perflogs\\*") 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer, TaskName, TaskContent 
|  rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `winevent_scheduled_task_created_within_public_path_filter`

Windows Scheduled Task with Suspicious Command

• source: splunk
• technicques:
  • T1053.005

Description

The following analytic detects the creation of scheduled tasks designed to execute commands using native Windows shells like PowerShell, Cmd, Wscript, or Cscript or from public folders such as Users, Temp, or ProgramData. It leverages Windows Security EventCode 4698, 4700, and 4702 to identify when such tasks are registered, enabled, or modified. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.

Detection logic

`wineventlog_security` EventCode IN (4698,4700,4702)

| eval TaskContent = case(isnotnull(TaskContentNew),TaskContentNew,true(),TaskContent)

| xmlkv TaskContent

| stats count min(_time) as firstTime max(_time) as lastTime latest(Arguments) as Arguments latest(Author) as Author by Computer, Caller_User_Name, TaskName, Command, Enabled, Hidden, EventCode

| lookup windows_suspicious_tasks task_command as Command 

| where tool == "shell command use" OR tool == "suspicious paths"

| eval command=TaskName, process=Command+if(isnotnull(Arguments)," ".Arguments,""), src_user=Author, user = Caller_User_Name, dest = Computer, signature_id = EventCode 

| `security_content_ctime(firstTime)` 

| `security_content_ctime(lastTime)`

| `windows_scheduled_task_with_suspicious_command_filter`