ID | Technique | Tactic |
---|---|---|
T1055 | Process Injection | Defense Evasion |
Detection: Splunk Process Injection Forwarder Bundle Downloads
Description
The following analytic identifies unauthorized forwarder bundle downloads from Splunk Deployment Servers. It leverages native Splunk logs, specifically the splunkd
component "PackageDownloadRestHandler," to detect instances where an unauthenticated client may have downloaded forwarder bundles. This activity is significant because it could indicate a potential security breach, allowing unauthorized access to sensitive configurations and applications. If confirmed malicious, an attacker could gain insights into the deployment server's environment, potentially leading to further exploitation or lateral movement within the network.
Search
1`splunkd` component="PackageDownloadRestHandler"
2| stats values(app) values(serverclass) by peer, host
3| `splunk_process_injection_forwarder_bundle_downloads_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
Splunk | Splunk | 'splunkd_ui_access' |
'splunkd_ui_access.log' |
N/A |
Macros Used
Name | Value |
---|---|
splunkd | index=_internal sourcetype=splunkd |
splunk_process_injection_forwarder_bundle_downloads_filter | search * |
splunk_process_injection_forwarder_bundle_downloads_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Risk Event | False |
Implementation
This hunting search uses native logs produced when a deployment server is within your environment. Splunk SOAR customers can find a SOAR workbook that walks an analyst through the process of running these hunting searches in the references list of this detection. In order to use this workbook, a user will need to run a curl command to post the file to their SOAR instance such as "curl -u username:password https://soar.instance.name/rest/rest/workbook_template -d @splunk_psa_0622.json". A user should then create an empty container or case, attach the workbook, and begin working through the tasks.
Known False Positives
None at this time.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
$peer$ downloaded apps from $host$ | 35 | 50 | 70 |
References
-
https://www.splunk.com/en_us/product-security/announcements/svd-2022-0607.html
-
https://www.github.com/splunk/security_content/blob/develop/workbooks/splunk_psa_0622.json
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | /opt/splunk/var/log/splunk/splunkd.log |
splunkd |
Integration | ✅ Passing | Dataset | /opt/splunk/var/log/splunk/splunkd.log |
splunkd |
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