Detect Baron Samedit CVE-2021-3156 Segfault
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.
This search detects the heap-based buffer overflow of sudoedit
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2021-01-29
- Author: Shannon Davis, Splunk
- ID: 10f2bae0-bbe6-4984-808c-37dc1c67980d
Kill Chain Phase
- CIS 8
- CIS 12
- CIS 16
|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 4 5 `linux_hosts` | search sudoedit segfault | stats count min(_time) as firstTime max(_time) as lastTime by host | search count > 5 | `detect_baron_samedit_cve_2021_3156_segfault_filter`
The SPL above uses the following Macros:
detect_baron_samedit_cve-2021-3156_segfault_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
Splunk Universal Forwarder running on Linux systems (tested on Centos and Ubuntu), where segfaults are being logged. This also captures instances where the exploit has been compiled into a binary. The detection looks for greater than 5 instances of sudoedit combined with segfault over your search time period on a single host
Known False Positives
If sudoedit is throwing segfaults for other reasons this will pick those up too.
Associated Analytic Story
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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