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 |
Privileged Account Management focuses on implementing policies, controls, and tools to securely manage privileged accounts (e.g., SYSTEM, root, or administrative accounts). This includes restricting access, limiting the scope of permissions, monitoring privileged account usage, and ensuring accountability through logging and auditing.This mitigation can be implemented through the following measures: Account Permissions and Roles: - Implement RBAC and least privilege principles to allocate permissions securely. - Use tools like Active Directory Group Policies to enforce access restrictions. Credential Security: - Deploy password vaulting tools like CyberArk, HashiCorp Vault, or KeePass for secure storage and rotation of credentials. - Enforce password policies for complexity, uniqueness, and expiration using tools like Microsoft Group Policy Objects (GPO). Multi-Factor Authentication (MFA): - Enforce MFA for all privileged accounts using Duo Security, Okta, or Microsoft Azure AD MFA. Privileged Access Management (PAM): - Use PAM solutions like CyberArk, BeyondTrust, or Thycotic to manage, monitor, and audit privileged access. Auditing and Monitoring: - Integrate activity monitoring into your SIEM (e.g., Splunk or QRadar) to detect and alert on anomalous privileged account usage. Just-In-Time Access: - Deploy JIT solutions like Azure Privileged Identity Management (PIM) or configure ephemeral roles in AWS and GCP to grant time-limited elevated permissions. *Tools for Implementation* Privileged Access Management (PAM): - CyberArk, BeyondTrust, Thycotic, HashiCorp Vault. Credential Management: - Microsoft LAPS (Local Admin Password Solution), Password Safe, HashiCorp Vault, KeePass. Multi-Factor Authentication: - Duo Security, Okta, Microsoft Azure MFA, Google Authenticator. Linux Privilege Management: - sudo configuration, SELinux, AppArmor. Just-In-Time Access: - Azure Privileged Identity Management (PIM), AWS IAM Roles with session constraints, GCP Identity-Aware Proxy. |
Multi-factor Authentication |
Multi-Factor Authentication (MFA) enhances security by requiring users to provide at least two forms of verification to prove their identity before granting access. These factors typically include: - *Something you know*: Passwords, PINs. - *Something you have*: Physical tokens, smartphone authenticator apps. - *Something you are*: Biometric data such as fingerprints, facial recognition, or retinal scans. Implementing MFA across all critical systems and services ensures robust protection against account takeover and unauthorized access. This mitigation can be implemented through the following measures: Identity and Access Management (IAM): - Use IAM solutions like Azure Active Directory, Okta, or AWS IAM to enforce MFA policies for all user logins, especially for privileged roles. - Enable conditional access policies to enforce MFA for risky sign-ins (e.g., unfamiliar devices, geolocations). Authentication Tools and Methods: - Use authenticator applications such as Google Authenticator, Microsoft Authenticator, or Authy for time-based one-time passwords (TOTP). - Deploy hardware-based tokens like YubiKey, RSA SecurID, or smart cards for additional security. - Enforce biometric authentication for compatible devices and applications. Secure Legacy Systems: - Integrate MFA solutions with older systems using third-party tools like Duo Security or Thales SafeNet. - Enable RADIUS/NPS servers to facilitate MFA for VPNs, RDP, and other network logins. Monitoring and Alerting: - Use SIEM tools to monitor failed MFA attempts, login anomalies, or brute-force attempts against MFA systems. - Implement alerts for suspicious MFA activities, such as repeated failed codes or new device registrations. Training and Policy Enforcement: - Educate employees on the importance of MFA and secure authenticator usage. - Enforce policies that require MFA on all critical systems, especially for remote access, privileged accounts, and cloud applications. |
Disable or Remove Feature or Program |
Disable or remove unnecessary and potentially vulnerable software, features, or services to reduce the attack surface and prevent abuse by adversaries. This involves identifying software or features that are no longer needed or that could be exploited and ensuring they are either removed or properly disabled. This mitigation can be implemented through the following measures: Remove Legacy Software: - Use Case: Disable or remove older versions of software that no longer receive updates or security patches (e.g., legacy Java, Adobe Flash). - Implementation: A company removes Flash Player from all employee systems after it has reached its end-of-life date. Disable Unused Features: - Use Case: Turn off unnecessary operating system features like SMBv1, Telnet, or RDP if they are not required. - Implementation: Disable SMBv1 in a Windows environment to mitigate vulnerabilities like EternalBlue. Control Applications Installed by Users: - Use Case: Prevent users from installing unauthorized software via group policies or other management tools. - Implementation: Block user installations of unauthorized file-sharing applications (e.g., BitTorrent clients) in an enterprise environment. Remove Unnecessary Services: - Use Case: Identify and disable unnecessary default services running on endpoints, servers, or network devices. - Implementation: Disable unused administrative shares (e.g., C$, ADMIN$) on workstations. Restrict Add-ons and Plugins: - Use Case: Remove or disable browser plugins and add-ons that are not needed for business purposes. - Implementation: Disable Java and ActiveX plugins in web browsers to prevent drive-by attacks. |
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 November 17, 2024.
- 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 November 17, 2024.
- 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
Мы используем cookie-файлы, чтобы получить статистику, которая помогает нам улучшить сервис для вас с целью персонализации сервисов и предложений. Вы может прочитать подробнее о cookie-файлах или изменить настройки браузера. Продолжая пользоваться сайтом, вы даёте согласие на использование ваших cookie-файлов и соглашаетесь с Политикой обработки персональных данных.