MailSniper

MailSniper is a penetration testing tool for searching through email in a Microsoft Exchange environment for specific terms (passwords, insider intel, network architecture information, etc.). It can be used as a non-administrative user to search their own email or by an Exchange administrator to search the mailboxes of every user in a domain.

MailSniper also includes additional modules for password spraying, enumerating users and domains, gathering the Global Address List (GAL) from OWA and EWS and checking mailbox permissions for every Exchange user at an organization.

Nice blog post with more information about here.

MailSniper Field Manual

Install:

git clone https://github.com/dafthack/MailSniper
cd MailSniper
Import-Module MailSniper.ps1

Usage:

# Search current users mailbox
Invoke-SelfSearch -Mailbox current-user@domain.com