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Description

On June 14th, 2022, Splunk released a security advisory relating to the authentication that happens between Universal Forwarders and Deployment Servers. In some circumstances, an unauthenticated client can download forwarder bundles from the Deployment Server. This hunting search pulls a full list of forwarder bundle downloads where the peer column is the forwarder, the host column is the Deployment Server, and then you have a list of the apps downloaded and the serverclasses in which the peer is a member of. You should look for apps or clients that you do not recognize as being part of your environment.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2022-05-26
  • Author: Lou Stella, Splunk
  • ID: 8ea57d78-1aac-45d2-a913-0cd603fb6e9e

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1055 Process Injection Defense Evasion, Privilege Escalation
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
1
2
3
`splunkd` component="PackageDownloadRestHandler" 
| stats values(app) values(serverclass) by peer, host 
| `splunk_process_injection_forwarder_bundle_downloads_filter`

Macros

The SPL above uses the following Macros:

:information_source: splunk_process_injection_forwarder_bundle_downloads_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • component
  • app
  • serverclass
  • peer
  • host

How To Implement

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

RBA

Risk Score Impact Confidence Message
35.0 50 70 $peer$ downloaded apps from $host$

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

Reference

Test Dataset

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 | version: 1