ESXi SSH Brute Force
Last updated 2 days ago on 2026-07-17
About
This detection identifies signs of SSH brute-force attacks by monitoring for a high number of failed login attempts within a short time frame. Such activity may indicate an attacker attempting to gain unauthorized access through password guessing.
- Platform
Splunk
- Tags
- Data Source: SplunkDomain: ApplicationRule Type: QueryOS: Any
- Severity
- medium
- Risk Score
- 47
- False Positives
- Limited false positives in most environments, however tune as needed.
- Source
- View on GitHub(external, opens in a new tab or window)
Definition
- Rule Language
- SPL
- Rule Type
- query
text code block:`esxi_syslog` Message="*Authentication failure for*" | rex "for (?<user>[\w]+) from (?<src_ip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})" | rex field=_raw "Z (?<dest>[\w\.]+)\s" | bin _time span=5m | stats min(_time) as firstTime max(_time) as lastTime count by user, src_ip, dest | where count > 10 | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_ssh_brute_force_filter`
View this rule on Splunk
This rule was sourced from the official Splunk public repository. View the original rule on GitHub(external, opens in a new tab or window).