Using FEC Remote Authenticator

FEC Remote Authenticator is a standalone application that you can provide to the owner of a Gmail, Google Workspace (formerly called G Suite), Office 365, or Microsoft consumer (e.g., Hotmail, email account so that they can authenticate you remotely. This can be especially useful when the custodian uses two-factor authentication. Using FEC Remote Authenticator, eDiscovery and digital forensics practitioners do not have to know the custodian's email password at all.

The remote authentication workflow works as follows:

Step 1

Custodian (owner of the mailbox) downloads a copy of FEC Remote Authenticator using the download link available on the Forensic Email Collector (FEC) user interface under the "Remote Authentication" menu.

FEC Remote Authenticator is a single EXE file that does not require extraction, installation, administrative privileges, or a license key. It does require that the custodian's computer have .NET framework 4.5 installed.

Step 2

The custodian runs FEC Remote Authenticator and authenticates with Gmail, Google Workspace, or Microsoft business or consumer accounts using the same workflow as FEC. FEC Remote Authenticator does not ask for the custodian's password; the password is provided directly to Google or Microsoft. If two-factor authentication is enabled, the custodian can perform the two-factor authentication via the Gmail or Microsoft web interface as usual.

Once authentication is complete, the following screen is displayed where the custodian can save an encrypted FEC Remote Authentication Token.

The saved token has a file name in the following format:


Once the token file is saved, the custodian can send the token file to you using the channel where you ordinarily exchange sensitive files with each other (e.g., file transfer system, secure FTP, etc.)

Step 3

Once you receive the token file, you can launch FEC and import it using the "Remote Authentication" menu as follows:

Once the token is imported, you can perform the acquisition without having to authenticate with Gmail, Google Workspace, Microsoft consumer accounts, or O365 on your end.

Step 4

Once email preservation is complete, the custodian can go to their account security settings and revoke access to FEC as follows:

Gmail / Google Workspace

1. Visit

2. Expand Forensic Email Collector and click the REMOVE ACCESS button.

Office 365

1. Visit

2. Click the Revoke button next to Forensic Email Collector.

Alternatively, if the user has an administrator role, you can control access to the Forensic Email Collector application via Microsoft Azure Portal as follows:

1. Visit

2. Navigate to Azure Active Directory > Enterprise Applications

3. Select the Forensic Email Collector application and click on Manage > Properties

Once access is removed, the FEC Remote Authentication Token will be invalidated. You can no longer use the token to access the custodian's emails.

Microsoft Consumer Accounts

  1. Visit
  2. Find the Forensic Email Collector entry and click Edit

  1. Click the Remove these permissions button

Advanced Scope Customization via Filename

By default, Remote Authenticator requests full access to Gmail and read-only access to Google Calendar and Drive. This is to accommodate all scenarios while keeping things simple—IMAP access to a Gmail / Google Workspace mailbox requires full permissions.

In some cases, you may prefer to customize the permissions that Remote Authenticator requests to fit your workflow. For example, if you are certain that you won't need IMAP access, there is no reason to request full Gmail permissions—you could go with read-only Gmail access instead.

It is possible to change Remote Authenticator's behavior on Windows by setting flags in the executable's filename. Valid flags are as follows:

R: Request read-only Gmail access. When not set, Remote Authenticator will request full Gmail access.

D: Request read-only Drive access. When not set, Remote Authenticator will not request access to Drive API.

C: Request read-only Calendar access. When not set, Remote Authenticator will not request access to Calendar API.

In order to set these flags, put them between a set of double underscores in the Remote Authenticator filename (e.g., __RDC__). Here are some examples:

FECRemoteAuthenticator_v1.11.1.exe    No flags are set. Default permissions will be requested (i.e., full Gmail, read-only Drive, read-only Calendar).

FECRemoteAuthenticator_v1.11.1__RDC__.exe    Read-only access to Gmail, Drive, and Calendar. This allows all API-based functionality, but not IMAP.

FECRemoteAuthenticator_v1.11.1__RC__.exe    Read-only access to Gmail, and Calendar. This allows an API-based Gmail acquisition with Google Calendar support but without Drive attachment support.

FECRemoteAuthenticator_v1.11.1__RD__.exe    Read-only access to Gmail, and Drive. This allows an API-based Gmail acquisition with Drive attachment support but without access to Google Calendar.

FECRemoteAuthenticator_v1.11.1__R__.exe    Read-only access to Gmail only. Suitable for API-based Gmail acquisitions without access to Google Calendar or Drive attachments.

FECRemoteAuthenticator_v1.11.1____.exe    This will only request full access to Gmail, but no access to Drive or Calendar. Suitable for IMAP acquisitions only.

Why Use the Filename for Scope Customization?

You might be wondering why the scope customization is done by using the filename of the executable rather than options within Remote Authenticator. The goal here is to allow the requestor to hard-code the scopes they need by setting the filename ahead of time. Otherwise, the requestor would have to provide further instructions to the end-user to choose the appropriate settings, which is not always desirable.

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