Detection: Schedule Task with HTTP Command Arguments

Updated Date: 2024-05-15 ID: 523c2684-a101-11eb-916b-acde48001122 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of scheduled tasks on Windows systems that include HTTP command arguments, using Windows Security EventCode 4698. It identifies tasks registered via schtasks.exe or TaskService with HTTP in their command arguments. This behavior is significant as it often indicates malware activity or the use of Living off the Land binaries (lolbins) to download additional payloads. If confirmed malicious, this activity could lead to data exfiltration, malware propagation, or unauthorized access to sensitive information, necessitating immediate investigation and mitigation.

1`wineventlog_security` EventCode=4698 
2| xmlkv Message
3| search Arguments IN ("*http*") 
4| stats count min(_time) as firstTime max(_time) as lastTime by dest, Task_Name, Command, Author, Enabled, Hidden, Arguments 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `schedule_task_with_http_command_arguments_filter`

Data Source

Name Platform Sourcetype Source Supported App
Windows Event Log Security 4698 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Security' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
schedule_task_with_http_command_arguments_filter search *
schedule_task_with_http_command_arguments_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1053 Scheduled Task/Job Execution
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
Earth Lusca

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search, you need to be ingesting logs with the task schedule (Exa. Security Log EventCode 4698) endpoints. Tune and filter known instances of Task schedule used in your environment.

Known False Positives

unknown

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
A schedule task process commandline arguments $Arguments$ with http string on it in host $dest$ 63 70 90
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset WinEventLog:Security WinEventLog
Integration ✅ Passing Dataset WinEventLog:Security WinEventLog

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 2