Account Manipulation: Выдача доп. прав учетной записи эл. почты Exchange
Other sub-techniques of Account Manipulation (7)
Adversaries may grant additional permission levels to maintain persistent access to an adversary-controlled email account.
For example, the Add-MailboxPermission
PowerShell cmdlet, available in on-premises Exchange and in the cloud-based service Office 365, adds permissions to a mailbox.(Citation: Microsoft - Add-MailboxPermission)(Citation: FireEye APT35 2018)(Citation: Crowdstrike Hiding in Plain Sight 2018) In Google Workspace, delegation can be enabled via the Google Admin console and users can delegate accounts via their Gmail settings.(Citation: Gmail Delegation)(Citation: Google Ensuring Your Information is Safe)
Adversaries may also assign mailbox folder permissions through individual folder permissions or roles. In Office 365 environments, adversaries may assign the Default or Anonymous user permissions or roles to the Top of Information Store (root), Inbox, or other mailbox folders. By assigning one or both user permissions to a folder, the adversary can utilize any other account in the tenant to maintain persistence to the target user’s mail folders.(Citation: Mandiant Defend UNC2452 White Paper)
This may be used in persistent threat incidents as well as BEC (Business Email Compromise) incidents where an adversary can add Additional Cloud Roles to the accounts they wish to compromise. This may further enable use of additional techniques for gaining access to systems. For example, compromised business accounts are often used to send messages to other accounts in the network of the target business while creating inbox rules (ex: Internal Spearphishing), so the messages evade spam/phishing detection mechanisms.(Citation: Bienstock, D. - Defending O365 - 2019)
Примеры процедур |
|
Название | Описание |
---|---|
During HomeLand Justice, threat actors added the `ApplicationImpersonation` management role to accounts under their control to impersonate users and take ownership of targeted mailboxes.(Citation: Microsoft Albanian Government Attacks September 2022) |
|
UNC2452 |
UNC2452 added their own devices as allowed IDs for active sync using |
During the SolarWinds Compromise, APT29 added their own devices as allowed IDs for active sync using `Set-CASMailbox`, allowing it to obtain copies of victim mailboxes. It also added additional permissions (such as Mail.Read and Mail.ReadWrite) to compromised Application or Service Principals.(Citation: Volexity SolarWinds)(Citation: Microsoft - Customer Guidance on Recent Nation-State Cyber Attacks)(Citation: MSTIC Nobelium Oct 2021) |
|
APT29 |
APT29 added their own devices as allowed IDs for active sync using |
Magic Hound |
Magic Hound granted compromised email accounts read access to the email boxes of additional targeted accounts. The group then was able to authenticate to the intended victim's OWA (Outlook Web Access) portal and read hundreds of email communications for information on Middle East organizations.(Citation: FireEye APT35 2018) |
APT28 |
APT28 has used a Powershell cmdlet to grant the |
APT29 |
APT29 has used a compromised global administrator account in Azure AD to backdoor a service principal with `ApplicationImpersonation` rights to start collecting emails from targeted mailboxes; APT29 has also used compromised accounts holding `ApplicationImpersonation` rights in Exchange to collect emails.(Citation: Mandiant APT29 Microsoft 365 2022)(Citation: Mandiant APT29 Eye Spy Email Nov 22) |
Контрмеры |
|
Контрмера | Описание |
---|---|
Privileged Account Management |
Manage the creation, modification, use, and permissions associated to privileged accounts, including SYSTEM and root. |
Multi-factor Authentication |
Use two or more pieces of evidence to authenticate to a system; such as username and password in addition to a token from a physical smart card or token generator. |
Disable or Remove Feature or Program |
Remove or deny access to unnecessary and potentially vulnerable software to prevent abuse by adversaries. |
Обнаружение
Monitor for unusual Exchange and Office 365 email account permissions changes that may indicate excessively broad permissions being granted to compromised accounts. Enable the UpdateFolderPermissions action for all logon types. The mailbox audit log will forward folder permission modification events to the Unified Audit Log. Create rules to alert on ModifyFolderPermissions operations where the Anonymous or Default user is assigned permissions other than None. A larger than normal volume of emails sent from an account and similar phishing emails sent from real accounts within a network may be a sign that an account was compromised and attempts to leverage access with modified email permissions is occurring.
Ссылки
- MSRC. (2020, December 13). Customer Guidance on Recent Nation-State Cyber Attacks. Retrieved December 30, 2020.
- Cash, D. et al. (2020, December 14). Dark Halo Leverages SolarWinds Compromise to Breach Organizations. Retrieved December 29, 2020.
- Microsoft Threat Intelligence Center. (2021, October 25). NOBELIUM targeting delegated administrative privileges to facilitate broader attacks. Retrieved March 25, 2022.
- Microsoft. (n.d.). Add-Mailbox Permission. Retrieved September 13, 2019.
- Mandiant. (2021, January 19). Remediation and Hardening Strategies for Microsoft 365 to Defend Against UNC2452. Retrieved January 22, 2021.
- Mandiant. (2018). Mandiant M-Trends 2018. Retrieved July 9, 2018.
- Google. (n.d.). Turn Gmail delegation on or off. Retrieved April 1, 2022.
- Google. (2011, June 1). Ensuring your information is safe online. Retrieved April 1, 2022.
- Crowdstrike. (2018, July 18). Hiding in Plain Sight: Using the Office 365 Activities API to Investigate Business Email Compromises. Retrieved January 19, 2020.
- Bienstock, D.. (2019). BECS and Beyond: Investigating and Defending O365. Retrieved September 13, 2019.
- MSTIC. (2022, September 8). Microsoft investigates Iranian attacks against the Albanian government. Retrieved August 6, 2024.
- NSA, CISA, FBI, NCSC. (2021, July). Russian GRU Conducting Global Brute Force Campaign to Compromise Enterprise and Cloud Environments. Retrieved July 26, 2021.
- Mandiant. (2022, May 2). UNC3524: Eye Spy on Your Email. Retrieved August 17, 2023.
- Douglas Bienstock. (2022, August 18). You Can’t Audit Me: APT29 Continues Targeting Microsoft 365. Retrieved February 23, 2023.
Связанные риски
Каталоги
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