Detection rules › Sigma

Schtasks Creation Or Modification With SYSTEM Privileges

Severity
high
Author
Nasreddine Bencherchali (Nextron Systems)
Source
upstream

Detects the creation or update of a scheduled task to run with "NT AUTHORITY\SYSTEM" privileges

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1053.005 Scheduled Task/Job: Scheduled Task
PersistenceT1053.005 Scheduled Task/Job: Scheduled Task
Privilege EscalationT1053.005 Scheduled Task/Job: Scheduled Task

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation
Security-Auditing4688A new process has been created.

Stages and Predicates

Stage 1: all of selection_root

or:
CommandLine|contains: ' /change '
CommandLine|contains: ' /create '
Image|endswith: '\schtasks.exe'

Stage 2: all of selection_run

CommandLine|contains: '/ru '

Stage 3: all of selection_user

or:
CommandLine|contains: ' SYSTEM '
CommandLine|contains: 'NT AUT'

Stage 4: not 1 of filter_optional_*

or:
CommandLine|contains: '/TN TVInstallRestore'
CommandLine|contains: '\TeamViewer_.exe'
Image|endswith: '\schtasks.exe'
CommandLine|contains: 'Subscription Heartbeat'
CommandLine|contains: '\HeartbeatConfig.xml'
CommandLine|contains: '\Microsoft Shared\OFFICE'
CommandLine|contains: '/Create /F /RU System /SC WEEKLY /TN AviraSystemSpeedupVerify /TR '
CommandLine|contains: '/VERIFY /VERYSILENT /NOSTART /NODOTNET /NORESTART" /RL HIGHEST'
CommandLine|contains: ':\Program Files (x86)\Avira\System Speedup\setup\avira_speedup_setup.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • /change corpus 2 (sigma 2)
  • /create corpus 14 (sigma 14)
  • SYSTEM corpus 2 (sigma 2)
  • /Create /F /RU System /SC WEEKLY /TN AviraSystemSpeedupVerify /TR
  • /TN TVInstallRestore corpus 2 (sigma 2)
  • /VERIFY /VERYSILENT /NOSTART /NODOTNET /NORESTART" /RL HIGHEST
  • /ru
  • :\Program Files (x86)\Avira\System Speedup\setup\avira_speedup_setup.exe
  • NT AUT corpus 4 (sigma 4)
  • Subscription Heartbeat
  • \HeartbeatConfig.xml
  • \Microsoft Shared\OFFICE
  • \TeamViewer_.exe
Imageends_with
  • \schtasks.exe corpus 45 (sigma 45)