: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 a specific type of vulnerability known as a heap-based buffer overflow in the sudoedit command, commonly referred to as Baron Samedit CVE-2021-3156. The detection is made by a Splunk query that searches for instances of the sudoedit command with the "-s" flag followed by a double quote. This combination of parameters is indicative of the vulnerability being exploited. The detection is important because it suggests that an attacker is attempting to exploit the Baron Samedit vulnerability. The Baron Samedit vulnerability allows an attacker to gain elevated privileges on a Linux system and run arbitrary code with root privileges, potentially leading to complete control over the affected system. The impact of a successful attack can be severe since it allows the attacker to bypass security measures and gain unauthorized access to sensitive data or systems. This can result in data breaches, unauthorized modifications, or even complete system compromise. Next steps include being aware of this vulnerability and actively monitoring any attempts to exploit it. By detecting and responding to such attacks in a timely manner, you can prevent or minimize the potential damage caused by the heap-based buffer overflow of sudoedit.

  • Type: TTP

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

  • Last Updated: 2021-01-27
  • Author: Shannon Davis, Splunk
  • ID: 93fbec4e-0375-440c-8db3-4508eca470c4

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



`linux_hosts` "sudoedit -s \\" 
| `detect_baron_samedit_cve_2021_3156_filter`

Macros

The SPL above uses the following Macros:

:information_source: detect_baron_samedit_cve-2021-3156_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

How To Implement

Splunk Universal Forwarder running on Linux systems, capturing logs from the /var/log directory. 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