Adversaries may attempt to get a listing of email addresses and accounts. Adversaries may try to dump Exchange address lists such as global address lists (GALs).(Citation: Microsoft Exchange Address Lists)

In on-premises Exchange and Exchange Online, the<code>Get-GlobalAddressList</code> PowerShell cmdlet can be used to obtain email addresses and accounts from a domain using an authenticated session.(Citation: Microsoft getglobaladdresslist)(Citation: Black Hills Attacking Exchange MailSniper, 2016)

In Google Workspace, the GAL is shared with Microsoft Outlook users through the Google Workspace Sync for Microsoft Outlook (GWSMO) service. Additionally, the Google Workspace Directory allows for users to get a listing of other users within the organization.(Citation: Google Workspace Global Access List)
Email Account
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1087/003  external_id: T1087.003     source_name: Microsoft Exchange Address Lists  description: Microsoft. (2020, February 7). Address lists in Exchange Server. Retrieved March 26, 2020.  url: https://docs.microsoft.com/en-us/exchange/email-addresses-and-address-books/address-lists/address-lists?view=exchserver-2019     source_name: Microsoft getglobaladdresslist  description: Microsoft. (n.d.). Get-GlobalAddressList. Retrieved October 6, 2019.  url: https://docs.microsoft.com/en-us/powershell/module/exchange/email-addresses-and-address-books/get-globaladdresslist     source_name: Black Hills Attacking Exchange MailSniper, 2016  description: Bullock, B.. (2016, October 3). Attacking Exchange with MailSniper. Retrieved October 6, 2019.  url: https://www.blackhillsinfosec.com/attacking-exchange-with-mailsniper/     source_name: Google Workspace Global Access List  description: Google. (n.d.). Retrieved March 16, 2021.  url: https://support.google.com/a/answer/166870?hl=en     