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.

Updated Date: 2024-05-11 ID: ec3b7601-689a-4463-94e0-c9f45638efb9 Author: David Dorsey, Splunk Type: TTP Product: Splunk Enterprise Security

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.

Search

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	`'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

Apache Struts Vulnerability

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