THIS IS A EXPERIMENTAL DETECTION
This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.
The following analytic identifies the process name of java.exe and w3wp.exe spawning a Windows shell. This is potentially indicative of exploitation of the Java application and may be related to current event CVE-2021-44228 (Log4Shell). The shells included in the macro are "cmd.exe", "powershell.exe". Upon triage, review parallel processes and command-line arguments to determine legitimacy.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2021-12-13
- Author: Michael Haag, Splunk
- ID: 28c81306-5c47-11ec-bfea-acde48001122
Kill Chain Phase
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=java.exe OR Processes.parent_process_name=w3wp.exe `windows_shells` by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_java_spawning_shells_filter`
The SPL above uses the following Macros:
windows_java_spawning_shells_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. Restrict the analytic to publicly facing endpoints to reduce false positives. Add any additional identified web application process name to the query. Add any further Windows process names to the macro (ex. LOLBins) to further expand this query.
Known False Positives
Filtering may be required on internal developer build systems or classify assets as web facing and restrict the analytic based on that.
Associated Analytic Story
|40.0||80||50||An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ spawning a Windows shell, potentially indicative of exploitation.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1