Detection: Windows LOLBAS Executed Outside Expected Path

Updated Date: 2024-11-13 ID: 326fdf44-b90c-4d2e-adca-1fd140b10536 Author: Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies a LOLBAS process being executed outside of it's expected location. Processes being executed outside of expected locations may be an indicator that an adversary is attempting to evade defenses or execute malicious code. The LOLBAS project documents Windows native binaries that can be abused by threat actors to perform tasks like executing malicious code.

Search

1
2|  tstats `security_content_summariesonly` latest(Processes.parent_process) as parent_process, latest(Processes.process) as process, latest(Processes.process_guid) as process_guid count, min(_time) AS firstTime, max(_time) AS lastTime FROM datamodel=Endpoint.Processes where Processes.process != "unknown" AND NOT Processes.process_path IN ("*\\Program Files*","*\\PROGRA~*","*\\Windows\\System32\\*","*\\Windows\\Syswow64\\*") BY Processes.user Processes.dest Processes.parent_process_name Processes.process_name Processes.process_path 
3|`drop_dm_object_name(Processes)` 
4| lookup lolbas_file_path lolbas_file_name as process_name OUTPUT description as desc 
5| lookup lolbas_file_path lolbas_file_name as process_name lolbas_file_path as process_path OUTPUT description as is_lolbas_path 
6| search desc!="false" AND is_lolbas_path="false" 
7| `security_content_ctime(firstTime)` 
8| `security_content_ctime(lastTime)` 
9| `windows_lolbas_executed_outside_expected_path_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 1	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`
Windows Event Log Security 4688	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_lolbas_executed_outside_expected_path_filter	`search *`

windows_lolbas_executed_outside_expected_path_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
T1036	Masquerading	Defense Evasion
T1036.005	Match Legitimate Name or Location	Defense Evasion
T1218.011	Rundll32	Defense Evasion

Exploitation

DE.CM

CIS 10

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 implement this search, you must ingest logs that contain the process name and process path, such as with Sysmon EID 1.

Known False Positives

Vendors will often copy system exectables to a different path for application usage.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

The user $user$ executed a LOLBAS [$process_name$] from an unexpected location on $dest$

Risk Object	Risk Object Type	Risk Score	Threat Objects
user	user	40	process_name
dest	system	40	process_name

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

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: 3