:warning: 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.

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Description

The following analytic detects the heap-based buffer overflow for the sudoedit command and identifies instances where the command "sudoedit -s *" is run using the osquery_process data source. This indicates that the sudoedit command is used with the "-s" flag, which is associated with the heap-based buffer overflow vulnerability. The detection is important because it indicates a potential security vulnerability, specifically Baron Samedit CVE-2021-3156, which helps to identify and respond to potential heap-based buffer overflow attacks to enhance the security posture of the organization. This vulnerability allows an attacker to escalate privileges and potentially gain unauthorized access to the system. If the attack is successful, the attacker can gain full control of the system, run arbitrary code, or access sensitive data. Such attacks can lead to data breaches, unauthorized access, and potential disruption of critical systems. False positives might occur since the legitimate use of the sudoedit command with the "-s" flag can also trigger this detection. You must carefully review and validate the findings before taking any action. Next steps include investigating all true positive detections promptly, reviewing the associated processes, gather relevant artifacts, identifying the source of the attack to contain the threat, mitigate the risks, and prevent further damage to the environment.

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

  • Last Updated: 2021-01-28
  • Author: Shannon Davis, Splunk
  • ID: 1de31d5d-8fa6-4ee0-af89-17069134118a

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1068 Exploitation for Privilege Escalation Privilege Escalation
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE
ID Summary CVSS
CVE-2021-3156 Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via "sudoedit -s" and a command-line argument that ends with a single backslash character. 7.2
1
2
3
`osquery_process` 
| search "columns.cmdline"="sudoedit -s \\*" 
| `detect_baron_samedit_cve_2021_3156_via_osquery_filter`

Macros

The SPL above uses the following Macros:

:information_source: detect_baron_samedit_cve-2021-3156_via_osquery_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
  • columns.cmdline

How To Implement

OSQuery installed and configured to pick up process events (info at https://osquery.io) as well as using the Splunk OSQuery Add-on https://splunkbase.splunk.com/app/4402. The vulnerability is exposed when a non privledged user tries passing in a single \ character at the end of the command while using the shell and edit flags.

Known False Positives

unknown

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 tbd

: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