Email Collection: Remote Email Collection

APT1 uses two utilities, GETMAIL and MAPIGET, to steal email. MAPIGET steals email still on Exchange servers that has not yet been archived.^[1]

APT28 has collected emails from victim Microsoft Exchange servers.^[2][3]

APT29 has collected emails from targeted mailboxes within a compromised Azure AD tenant and compromised Exchange servers, including via Exchange Web Services (EWS) API requests.^[4][5]

Chimera has harvested data from remote mailboxes including through execution of \\c$\Users\\AppData\Local\Microsoft\Outlook*.ost.^[6]

Dragonfly has accessed email accounts using Outlook Web Access.^[7]

FIN4 has accessed and hijacked online email communications using stolen credentials.^[8][9]

HAFNIUM has used web shells to export mailbox data.^[10][11]

During HomeLand Justice, threat actors made multiple HTTP POST requests to the Exchange servers of the victim organization to transfer data.^[12]

Ke3chang has used compromised credentials and a .NET tool to dump data from Microsoft Exchange mailboxes.^[13][14]

Kimsuky has used tools such as the MailFetch mail crawler to collect victim emails (excluding spam) from online services via IMAP.^[15]

Leafminer used a tool called MailSniper to search through the Exchange server mailboxes for keywords.^[16]

LightNeuron collects Exchange emails matching rules specified in its configuration.^[17]

Magic Hound has exported emails from compromised Exchange servers including through use of the cmdlet New-MailboxExportRequest.^[18][19]

MailSniper can be used for searching through email in Exchange and Office 365 environments.^[20]

Some SeaDuke samples have a module to extract email from Microsoft Exchange servers using compromised credentials.^[21]

During the SolarWinds Compromise, APT29 collected emails from specific individuals, such as executives and IT staff, using New-MailboxExportRequest followed by Get-MailboxExportRequest.^[22][23]

Star Blizzard has remotely accessed victims' email accounts to steal messages and attachments.^[24]

Valak can collect sensitive mailing information from Exchange servers, including credentials and the domain certificate of an enterprise.^[25]

Use of encryption provides an added layer of security to sensitive information sent over email. Encryption using public key cryptography requires the adversary to obtain the private certificate along with an encryption key to decrypt messages.

Use of multi-factor authentication for public-facing webmail servers is a recommended best practice to minimize the usefulness of usernames and passwords to adversaries.

Use secure out-of-band authentication methods to verify the authenticity of critical actions initiated via email, such as password resets, financial transactions, or access requests.

For highly sensitive information, utilize out-of-band communication channels instead of relying solely on email. This reduces the risk of sensitive data being collected through compromised email accounts.

Set up out-of-band alerts to notify security teams of unusual email activities, such as mass forwarding or large attachments being sent, which could indicate email collection attempts.

Create plans for leveraging a secure out-of-band communications channel, rather than an existing in-network email server, in case of a security incident.^[26]