How to Detect Failed Logon Attempts to VMware®

To list all failed logon attempts

1. In the VMware® vSphere® client, while connected to VMware® vCenter Server®, click Events in the Management section.
2. In the Description, Type or Target contains field, type

cannot login

A list of recent failed logon attempts will be displayed with the following details:

• The Description field lists the username and IP address from which the connection was attempted.
• If the failed login attempt was made to an VMware® ESX®/VMware® ESXi™host, the Target field lists the ESX/ESXi hostname or IP address. The Target field will be blank if the failed login attempt was to vCenter Server.

To report on events within a specific date range

Note: This method does not distinguish between failed logins to ESX/ESXi hosts and failed logins to the vCenter Server.

1. In the vSphere Client, while connected to vCenter Server, click File > Export > Export Events.
2. Enter a file name and location.
3. Deselect the Warning and Information Severity options.
4. Select a date/time range.
5. Click OK. 
   Note: This process may take some time in large environments. A progress indicator is shown at the bottom of the Export Events screen. 
6. Open the resulting file in a text editor and search for cannot login to find failed login attempts.

Using VMware® Power CLI

This sample script generates a list of failed logins to ESX/ESXi hosts managed by vCenter Server between 10/11/2019 and 13/11/2019:

connect-viserver -server vCenter Server hostname

$hostevents = Get-VIEvent -start 10/11/2019 -finish 13/11/2019 -maxsamples 100000 | where-object {$_.Host.Name -notlike ""}

foreach ($event in $hostevents) {if ($event.fullFormattedMessage -match "Cannot login (.*)@(.*)") {Write-Host ("User " + $matches[1] + " failed to login to " + $event.Host.Name + " from " + $matches[2] + " at: " + $event.createdTime)} }

Sample output:

User root failed to login vm01.enterprise.com from 192.168.1.66 at: 12/11/2019 15:51:25
User jmclaren failed to login vm01.enterprise.com from 192.168.1.66 at: 12/11/2019 17:02:51

Note that:

• In large environments, processing may take some time.
• If you suspect that not all results are being returned, set the -maxsamples parameter higher.
• Available events depend upon your retention policy. If your retention policy is set for 10 days, data about failed logons from 20 days ago won’t be available.
• You need to have sufficient permissions to export the events.