Linux c99 Privilege Escalation
Description
The c99 utility is an interface to the standard C compilation system; it shall accept source code conforming to the ISO C standard. The system conceptually consists of a compiler and link editor. If sudo right is given to ruby application for the user, then the user can run system commands as root and possibly get a root shell.
- Type: Anomaly
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-08-11
- Author: Gowthamaraj Rajendran, Splunk
- ID: e1c6dec5-2249-442d-a1f9-99a4bd228183
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- DE.AE
CIS20
- CIS 10
CVE
Search
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.process="*c99*" AND Processes.process="*-wrapper*" AND Processes.process="*sudo*" by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.process_guid
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `linux_c99_privilege_escalation_filter`
Macros
The SPL above uses the following Macros:
linux_c99_privilege_escalation_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.
- _time
- Processes.dest
- Processes.user
- Processes.parent_process_name
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_id
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 into the Endpoint datamodel. If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.
Known False Positives
False positives may be present, filter as needed.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
30.0 | 60 | 50 | An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ |
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
- https://gtfobins.github.io/gtfobins/c99/
- https://pubs.opengroup.org/onlinepubs/009604499/utilities/c99.html
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