Detection: Web Servers Executing Suspicious Processes

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Description

The following analytic detects the execution of suspicious processes on systems identified as web servers. It leverages the Splunk data model "Endpoint.Processes" to search for specific process names such as "whoami", "ping", "iptables", "wget", "service", and "curl". This activity is significant because these processes are often used by attackers for reconnaissance, persistence, or data exfiltration. If confirmed malicious, this could lead to data theft, deployment of additional malware, or even ransomware attacks. Immediate investigation is required to determine the legitimacy of the activity and mitigate potential threats.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.dest_category="web_server" AND (Processes.process="*whoami*" OR Processes.process="*ping*" OR Processes.process="*iptables*" OR Processes.process="*wget*" OR Processes.process="*service*" OR Processes.process="*curl*") by Processes.process Processes.process_name, Processes.dest Processes.user
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `web_servers_executing_suspicious_processes_filter`

Data Source

Name Platform Sourcetype Source Supported App
Sysmon EventID 1 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
web_servers_executing_suspicious_processes_filter search *
web_servers_executing_suspicious_processes_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
T1082 System Information Discovery Discovery
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT18
APT19
APT3
APT32
APT37
APT38
APT41
Aquatic Panda
Blue Mockingbird
Chimera
Confucius
Darkhotel
FIN13
FIN8
Gamaredon Group
HEXANE
Higaisa
Inception
Ke3chang
Kimsuky
Lazarus Group
Magic Hound
Malteiro
Moses Staff
MuddyWater
Mustang Panda
Mustard Tempest
OilRig
Patchwork
Rocke
Sandworm Team
SideCopy
Sidewinder
Sowbug
Stealth Falcon
TA2541
TeamTNT
ToddyCat
Tropic Trooper
Turla
Volt Typhoon
Windigo
Windshift
Wizard Spider
ZIRCONIUM
admin@338

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

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

Some of these processes may be used legitimately on web servers during maintenance or other administrative tasks.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
tbd 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit ❌ Failing N/A N/A N/A
Integration ❌ Failing N/A N/A N/A

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