Detection: Java Writing JSP File

Updated Date: 2024-11-13 ID: eb65619c-4f8d-4383-a975-d352765d344b Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the Java process writing a .jsp file to disk, which may indicate a web shell being deployed. It leverages data from the Endpoint datamodel, specifically monitoring process and filesystem activities. This activity is significant because web shells can provide attackers with remote control over the compromised server, leading to further exploitation. If confirmed malicious, this could allow unauthorized access, data exfiltration, or further compromise of the affected system, posing a severe security risk.

Search

 1
 2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where Processes.process_name IN ("java","java.exe", "javaw.exe") by _time Processes.process_id Processes.process_name Processes.dest Processes.process_guid Processes.user 
 3| `drop_dm_object_name(Processes)` 
 4| join process_guid [
 5| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Filesystem where Filesystem.file_name="*.jsp*" by _time Filesystem.dest Filesystem.file_create_time Filesystem.file_name Filesystem.file_path Filesystem.process_guid Filesystem.user 
 6| `drop_dm_object_name(Filesystem)` 
 7| fields _time process_guid file_path file_name file_create_time user dest process_name] 
 8| stats count min(_time) as firstTime max(_time) as lastTime by dest process_name process_guid file_name file_path file_create_time user 
 9| `security_content_ctime(firstTime)` 
10| `security_content_ctime(lastTime)` 
11| `java_writing_jsp_file_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 1	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`
Sysmon EventID 11	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

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

java_writing_jsp_file_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
T1190	Exploit Public-Facing Application	Initial Access
T1133	External Remote Services	Initial Access

Delivery

Installation

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 successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes and Filesystem node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

False positives are possible and filtering may be required. Restrict by assets or filter known jsp files that are common for the environment.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

An instance of $process_name$ was identified on endpoint $dest$ writing a jsp file $file_name$ to disk, potentially indicative of exploitation.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	42	process_name

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`Syslog:Linux-Sysmon/Operational`	`sysmon:linux`
Integration	✅ Passing	Dataset	`Syslog:Linux-Sysmon/Operational`	`sysmon:linux`

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: 6