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Name: Office Application Startup: Outlook Forms
Description: Adversaries may abuse Microsoft Outlook forms to obtain persistence on a compromised system. Outlook forms are used as templates for presentation and functionality in Outlook messages. Custom Outlook forms can be created that will execute code when a specifically crafted email is sent by an adversary utilizing the same custom Outlook form. Once malicious forms have been added to the user’s mailbox, they will be loaded when Outlook is started. Malicious forms will execute when an adversary sends a specifically crafted email to the user.
Tactics: Persistence
Platforms Affected: Office 365, Windows
Detection Strategies: Microsoft has released a PowerShell script to safely gather mail forwarding rules and custom forms in your mail environment as well as steps to interpret the output. SensePost, whose tool Ruler can be used to carry out malicious rules, forms, and Home Page attacks, has released a tool to detect Ruler usage. Collect process execution information including process IDs (PID) and parent process IDs (PPID) and look for abnormal chains of activity resulting from Office processes. Non-standard process execution trees may also indicate suspicious or malicious behavior.
More Information: https://attack.mitre.org/techniques/T1137/003
Technique ID: T1137.004
Name: Office Application Startup: Outlook Home Page
Description: Adversaries may abuse Microsoft Outlook's Home Page feature to obtain persistence on a compromised system. Outlook Home Page is a legacy feature used to customize the presentation of Outlook folders. This feature allows for an internal or external URL to be loaded and presented whenever a folder is opened. A malicious HTML page can be crafted that will execute code when loaded by Outlook Home Page. Once malicious home pages have been added to the user’s mailbox, they will be loaded when Outlook is started. Malicious Home Pages will execute when the right Outlook folder is loaded/reloaded.
Tactics: Persistence
Platforms Affected: Office 365, Windows
Detection Strategies: Microsoft has released a PowerShell script to safely gather mail forwarding rules and custom forms in your mail environment as well as steps to interpret the output. SensePost, whose tool Ruler can be used to carry out malicious rules, forms, and Home Page attacks, has released a tool to detect Ruler usage. Collect process execution information including process IDs (PID) and parent process IDs (PPID) and look for abnormal chains of activity resulting from Office processes. Non-standard process execution trees may also indicate suspicious or malicious behavior.
More Information: https://attack.mitre.org/techniques/T1137/004
Technique ID: T1137.005
Name: Office Application Startup: Outlook Rules
Description: Adversaries may abuse Microsoft Outlook rules to obtain persistence on a compromised system. Outlook rules allow a user to define automated behavior to manage email messages. A benign rule might, for example, automatically move an email to a particular folder in Outlook if it contains specific words from a specific sender. Malicious Outlook rules can be created that can trigger code execution when an adversary sends a specifically crafted email to that user. Once malicious rules have been added to the user’s mailbox, they will be loaded when Outlook is started. Malicious rules will execute when an adversary sends a specifically crafted email to the user.
Tactics: Persistence
Platforms Affected: Office 365, Windows
Detection Strategies: Microsoft has released a PowerShell script to safely gather mail forwarding rules and custom forms in your mail environment as well as steps to interpret the output. This PowerShell script is ineffective in gathering rules with modified `PRPRMSGRULEPROVIDER` properties caused by adversaries using a Microsoft Exchange Server Messaging API Editor (MAPI Editor), so only examination with the Exchange Administration tool MFCMapi can reveal these mail forwarding rules. SensePost, whose tool Ruler can be used to carry out malicious rules, forms, and Home Page attacks, has released a tool to detect Ruler usage. Collect process execution information including process IDs (PID) and parent process IDs (PPID) and look for abnormal chains of activity resulting from Office processes. Non-standard process execution trees may also indicate suspicious or malicious behavior.
More Information: https://attack.mitre.org/techniques/T1137/005
Technique ID: T1548
Name: Abuse Elevation Control Mechanism
Description: Adversaries may circumvent mechanisms designed to control elevate privileges to gain higher-level permissions. Most modern systems contain native elevation control mechanisms that are intended to limit privileges that a user can perform on a machine. Authorization has to be granted to specific users in order to perform tasks that can be considered of higher risk. An adversary can perform several methods to take advantage of built-in control mechanisms in order to escalate privileges on a system.
Tactics: Defense Evasion, Privilege Escalation
Platforms Affected: Azure AD, Google Workspace, IaaS, Linux, Office 365, Windows, macOS
Detection Strategies: Monitor the file system for files that have the setuid or setgid bits set. Also look for any process API calls for behavior that may be indicative of Process Injection and unusual loaded DLLs through DLL Search Order Hijacking, which indicate attempts to gain access to higher privileged processes. On Linux, auditd can alert every time a user's actual ID and effective ID are different (this is what happens when you sudo). Consider monitoring for /usr/libexec/securityINPUT and LOG_OUTPUT directives in the /etc/sudoers file. There are many ways to perform UAC bypasses when a user is in the local administrator group on a system, so it may be difficult to target detection on all variations. Efforts should likely be placed on mitigation and collecting enough information on process launches and actions that could be performed before and after a UAC bypass is performed. Some UAC bypass methods rely on modifying specific, user-accessible Registry settings. Analysts should monitor Registry settings for unauthorized changes.
More Information: https://attack.mitre.org/techniques/T1548
Technique ID: T1548.005
Name: Abuse Elevation Control Mechanism: Temporary Elevated Cloud Access
Description: Adversaries may abuse permission configurations that allow them to gain temporarily elevated access to cloud resources. Many cloud environments allow administrators to grant user or service accounts permission to request just-in-time access to roles, impersonate other accounts, pass roles onto resources and services, or otherwise gain short-term access to a set of privileges that may be distinct from their own. Just-in-time access is a mechanism for granting additional roles to cloud accounts in a granular, temporary manner. This allows accounts to operate with only the permissions they need on a daily basis, and to request additional permissions as necessary. Sometimes just-in-time access requests are configured to require manual approval, while other times the desired permissions are automatically granted. Account impersonation allows user or service accounts to temporarily act with the permissions of another account. For example, in GCP users with the `iam.serviceAccountTokenCreator` role can create temporary access tokens or sign arbitrary payloads with the permissions of a service account. In Exchange Online, the `ApplicationImpersonation` role allows a service account to use the permissions associated with specified user accounts. Many cloud environments also include mechanisms for users to pass roles to resources that allow them to perform tasks and authenticate to other services. While the user that creates the resource does not directly assume the role they pass to it, they may still be able to take advantage of the role's access -- for example, by configuring the resource to perform certain actions with the permissions it has been granted. In AWS, users with the `PassRole` permission can allow a service they create to assume a given role, while in GCP, users with the `iam.serviceAccountUser` role can attach a service account to a resource. While users require specific role assignments in order to use any of these features, cloud administrators may misconfigure permissions. This could result in escalation paths that allow adversaries to gain access to resources beyond what was originally intended. Note: this technique is distinct from Additional Cloud Roles, which involves assigning permanent roles to accounts rather than abusing existing permissions structures to gain temporarily elevated access to resources. However, adversaries that compromise a sufficiently privileged account may grant another account they control Additional Cloud Roles that would allow them to also abuse these features. This may also allow for greater stealth than would be had by directly using the highly privileged account, especially when logs do not clarify when role impersonation is taking place.
Tactics: Defense Evasion, Privilege Escalation
Platforms Affected: Azure AD, IaaS, Office 365
Detection Strategies: No detection description provided.
More Information: https://attack.mitre.org/techniques/T1548/005
Technique ID: T1484
Name: Domain Policy Modification
Description: Adversaries may modify the configuration settings of a domain to evade defenses and/or escalate privileges in domain environments. Domains provide a centralized means of managing how computer resources (ex: computers, user accounts) can act, and interact with each other, on a network. The policy of the domain also includes configuration settings that may apply between domains in a multi-domain/forest environment. Modifications to domain settings may include altering domain Group Policy Objects (GPOs) or changing trust settings for domains, including federation trusts. With sufficient permissions, adversaries can modify domain policy settings. Since domain configuration settings control many of the interactions within the Active Directory (AD) environment, there are a great number of potential attacks that can stem from this abuse. Examples of such abuse include modifying GPOs to push a malicious Scheduled Task to computers throughout the domain environment or modifying domain trusts to include an adversary controlled domain where they can control access tokens that will subsequently be accepted by victim domain resources. Adversaries can also change configuration settings within the AD environment to implement a Rogue Domain Controller. Adversaries may temporarily modify domain policy, carry out a malicious action(s), and then revert the change to remove suspicious indicators.
Tactics: Defense Evasion, Privilege Escalation
Platforms Affected: Azure AD, Windows
Detection Strategies: It may be possible to detect domain policy modifications using Windows event logs. Group policy modifications, for example, may be logged under a variety of Windows event IDs for modifying, creating, undeleting, moving, and deleting directory service objects (Event ID 5136, 5137, 5138, 5139, 5141 respectively). Monitor for modifications to domain trust settings, such as when a user or application modifies the federation settings on the domain or updates domain authentication from Managed to Federated via ActionTypes Set federation settings on domain and Set domain authentication. This may also include monitoring for Event ID 307 which can be correlated to relevant Event ID 510 with the same Instance ID for change details. Consider monitoring for commands/cmdlets and command-line arguments that may be leveraged to modify domain policy settings. Some domain policy modifications, such as changes to federation settings, are likely to be rare.
More Information: https://attack.mitre.org/techniques/T1484
Technique ID: T1484.002
Name: Domain Policy Modification: Domain Trust Modification
Description: Adversaries may add new domain trusts or modify the properties of existing domain trusts to evade defenses and/or elevate privileges. Domain trust details, such as whether or not a domain is federated, allow authentication and authorization properties to apply between domains for the purpose of accessing shared resources. These trust objects may include accounts, credentials, and other authentication material applied to servers, tokens, and domains. Manipulating the domain trusts may allow an adversary to escalate privileges and/or evade defenses by modifying settings to add objects which they control. For example, this may be used to forge SAML Tokens, without the need to compromise the signing certificate to forge new credentials. Instead, an adversary can manipulate domain trusts to add their own signing certificate. An adversary may also convert a domain to a federated domain, which may enable malicious trust modifications such as altering the claim issuance rules to log in any valid set of credentials as a specified user.
Tactics: Defense Evasion, Privilege Escalation
Platforms Affected: Azure AD, Windows
Detection Strategies: Monitor for modifications to domain trust settings, such as when a user or application modifies the federation settings on the domain or updates domain authentication from Managed to Federated via ActionTypes Set federation settings on domain and Set domain authentication. This may also include monitoring for Event ID 307 which can be correlated to relevant Event ID 510 with the same Instance ID for change details. Monitor for PowerShell commands such as: Update-MSOLFederatedDomain –DomainName: "Federated Domain Name", or Update-MSOLFederatedDomain –DomainName: "Federated Domain Name" –supportmultipledomain.
More Information: https://attack.mitre.org/techniques/T1484/002
Technique ID: T1211
Name: Exploitation for Defense Evasion
Description: Adversaries may exploit a system or application vulnerability to bypass security features. Exploitation of a vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Vulnerabilities may exist in defensive security software that can be used to disable or circumvent them. Adversaries may have prior knowledge through reconnaissance that security software exists within an environment or they may perform checks during or shortly after the system is compromised for Security Software Discovery. The security software will likely be targeted directly for exploitation. There are examples of antivirus software being targeted by persistent threat groups to avoid detection. There have also been examples of vulnerabilities in public cloud infrastructure of SaaS applications that may bypass defense boundaries , evade security logs , or deploy hidden infrastructure.
Tactics: Defense Evasion
Platforms Affected: IaaS, Linux, SaaS, Windows, macOS
Detection Strategies: Exploitation for defense evasion may happen shortly after the system has been compromised to prevent detection during later actions for for additional tools that may be brought in and used. Detecting software exploitation may be difficult depending on the tools available. Software exploits may not always succeed or may cause the exploited process to become unstable or crash. Also look for behavior on the system that might indicate successful compromise, such as abnormal behavior of processes. This could include suspicious files written to disk, evidence of Process Injection for attempts to hide execution or evidence of Discovery.
More Information: https://attack.mitre.org/techniques/T1211
Technique ID: T1564
Name: Hide Artifacts
Description: Adversaries may attempt to hide artifacts associated with their behaviors to evade detection. Operating systems may have features to hide various artifacts, such as important system files and administrative task execution, to avoid disrupting user work environments and prevent users from changing files or features on the system. Adversaries may abuse these features to hide artifacts such as files, directories, user accounts, or other system activity to evade detection. Adversaries may also attempt to hide artifacts associated with malicious behavior by creating computing regions that are isolated from common security instrumentation, such as through the use of virtualization technology.
Tactics: Defense Evasion
Platforms Affected: Linux, Office 365, Windows, macOS
Detection Strategies: Monitor files, processes, and command-line arguments for actions indicative of hidden artifacts. Monitor event and authentication logs for records of hidden artifacts being used. Monitor the file system and shell commands for hidden attribute usage.
More Information: https://attack.mitre.org/techniques/T1564
Technique ID: T1564.008
Name: Hide Artifacts: Email Hiding Rules
Description: Adversaries may use email rules to hide inbound emails in a compromised user's mailbox. Many email clients allow users to create inbox rules for various email functions, including moving emails to other folders, marking emails as read, or deleting emails. Rules may be created or modified within email clients or through external features such as the New-InboxRule or Set-InboxRule PowerShell cmdlets on Windows systems. Adversaries may utilize email rules within a compromised user's mailbox to delete and/or move emails to less noticeable folders. Adversaries may do this to hide security alerts, C2 communication, or responses to Internal Spearphishing emails sent from the compromised account. Any user or administrator within the organization (or adversary with valid credentials) may be able to create rules to automatically move or delete emails. These rules can be abused to impair/delay detection had the email content been immediately seen by a user or defender. Malicious rules commonly filter out emails based on key words (such as malware, suspicious, phish, and hack) found in message bodies and subject lines. In some environments, administrators may be able to enable email rules that operate organization-wide rather than on individual inboxes. For example, Microsoft Exchange supports transport rules that evaluate all mail an organization receives against user-specified conditions, then performs a user-specified action on mail that adheres to those conditions. Adversaries that abuse such features may be able to automatically modify or delete all emails related to specific topics (such as internal security incident notifications).
Tactics: Defense Evasion
Platforms Affected: Google Workspace, Linux, Office 365, Windows, macOS
Detection Strategies: Monitor email clients and applications for suspicious activity, such as missing messages or abnormal configuration and/or log entries. On Windows systems, monitor for creation of suspicious inbox rules through the use of the New-InboxRule and Set-InboxRule PowerShell cmdlets. On MacOS systems, monitor for modifications to the RulesActiveState.plist, SyncedRules.plist, UnsyncedRules.plist, and MessageRules.plist files.
More Information: https://attack.mitre.org/techniques/T1564/008
Technique ID: T1562
Name: Impair Defenses
Description: Adversaries may maliciously modify components of a victim environment in order to hinder or disable defensive mechanisms. This not only involves impairing preventative defenses, such as firewalls and anti-virus, but also detection capabilities that defenders can use to audit activity and identify malicious behavior. This may also span both native defenses as well as supplemental capabilities installed by users and administrators. Adversaries may also impair routine operations that contribute to defensive hygiene, such as blocking users from logging out of a computer or stopping it from being shut down. These restrictions can further enable malicious operations as well as the continued propagation of incidents. Adversaries could also target event aggregation and analysis mechanisms, or otherwise disrupt these procedures by altering other system components.
Tactics: Defense Evasion
Platforms Affected: Containers, IaaS, Linux, Network, Office 365, Windows, macOS
Detection Strategies: Monitor processes and command-line arguments to see if security tools or logging services are killed or stop running. Monitor Registry edits for modifications to services and startup programs that correspond to security tools. Lack of log events may be suspicious. Monitor environment variables and APIs that can be leveraged to disable security measures.
More Information: https://attack.mitre.org/techniques/T1562
Technique ID: T1562.007
Name: Impair Defenses: Disable or Modify Cloud Firewall