Email Collection: Remote Email Collection

Adversaries may target an Exchange server, Office 365, or Google Workspace to collect sensitive information. Adversaries may leverage a user's credentials and interact directly with the Exchange server to acquire information from within a network. Adversaries may also access externally facing Exchange services, Office 365, or Google Workspace to access email using credentials or access tokens. Tools such as MailSniper can be used to automate searches for specific keywords.

ID: T1114.002
Sub-technique of:  T1114
Tactic: Collection
Platforms: Google Workspace, Office 365, Windows
Data Sources: Command: Command Execution, Logon Session: Logon Session Creation, Network Traffic: Network Connection Creation
Version: 1.1
Created: 19 February 2020
Last Modified: 25 March 2021

Procedure Examples

ID Name Description
G0006 APT1

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 MAPIGET steals email still on Exchange servers that has not yet been archived.[1]

G0007 APT28

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

G0016 APT29

APT29 collected emails from specific individuals, such as executives and IT staff, using New-MailboxExportRequest followed by Get-MailboxExportRequest.[3]

G0114 Chimera

Chimera has harvested data from remote mailboxes including through execution of \\c$\Users\\AppData\Local\Microsoft\Outlook*.ost.[4]

G0074 Dragonfly 2.0

Dragonfly 2.0 accessed email accounts using Outlook Web Access.[5]

G0085 FIN4

FIN4 has accessed and hijacked online email communications using stolen credentials.[6][7]

G0125 HAFNIUM

HAFNIUM has used web shells to export mailbox data.[8][9]

G0004 Ke3chang

Ke3chang used a .NET tool to dump data from Microsoft Exchange mailboxes.[10]

G0077 Leafminer

Leafminer used a tool called MailSniper to search through the Exchange server mailboxes for keywords.[11]

S0395 LightNeuron

LightNeuron collects Exchange emails matching rules specified in its configuration.[12]

S0413 MailSniper

MailSniper can be used for searching through email in Exchange and Office 365 environments.[13]

S0053 SeaDuke

Some SeaDuke samples have a module to extract email from Microsoft Exchange servers using compromised credentials.[14]

S0476 Valak

Valak can collect sensitive mailing information from Exchange servers, including credentials and the domain certificate of an enterprise.[15]

Mitigations

ID Mitigation Description
M1041 Encrypt Sensitive Information

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.

M1032 Multi-factor Authentication

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.

Detection

Monitor for unusual login activity from unknown or abnormal locations, especially for privileged accounts (ex: Exchange administrator account).

References