Office Template Macros
Office Template Macros [T1137.001]
Information
Introduction
Office Template Macros (T1137.001) is a sub-technique within the MITRE ATT&CK framework under the broader category of Office Application Startup (T1137). It involves adversaries leveraging Microsoft Office template files (.dotm, .dotx, .xltm, .potm) containing malicious macros to execute unauthorized commands or payloads. These macros are typically embedded within legitimate-looking templates, automatically executing when users create or open documents based on these templates. This sub-technique exploits the trust relationship users have with Office documents and the automatic macro execution feature, making it a popular and effective vector for initial access, persistence, or lateral movement.
Deep Dive Into Technique
Office Template Macros exploit Microsoft Office's built-in template functionality, specifically targeting macro-enabled template files (.dotm, .xltm, .potm). These templates can be stored locally or remotely, and Office applications automatically load and execute macros from templates upon opening new documents or presentations based on these templates.
Technical execution details include:
Template Storage Locations:
Default user template directories (e.g.,
%APPDATA%\Microsoft\Templates\)Shared template locations on network drives or SharePoint sites
Remote URLs specified in documents to fetch templates dynamically
Macro Execution Mechanism:
Macros embedded in templates execute automatically upon user interaction (e.g., creating or opening a document based on the malicious template).
Adversaries can leverage VBA (Visual Basic for Applications) scripts embedded in templates to perform malicious actions, including:
Downloading additional payloads
Establishing command-and-control (C2) channels
Executing PowerShell or command-line scripts
Modifying registry keys for persistence
Delivery Methods:
Phishing emails containing documents referencing malicious templates
Compromised legitimate websites hosting malicious templates
Internal lateral movement by placing malicious templates in shared directories or network locations
Obfuscation Techniques:
Encoding or encrypting macros to bypass signature-based antivirus detection
Utilizing VBA obfuscation tools to hide macro functionality and evade static analysis
Embedding macros within legitimate-looking templates to reduce suspicion
When this Technique is Usually Used
Office Template Macros frequently appear across multiple stages of the attack lifecycle, including:
Initial Access:
Attackers commonly deliver malicious templates via phishing campaigns to gain initial footholds in victim environments.
Users unknowingly execute malicious macros when opening seemingly legitimate Office documents.
Execution:
Malicious macros execute automatically, enabling attackers to run arbitrary code without explicit user consent beyond initial template loading.
Persistence:
Attackers store malicious templates in default template directories or shared network locations, ensuring repeated execution whenever users create new documents based on these templates.
Lateral Movement:
Attackers may place malicious templates in shared directories accessible by multiple users, enabling lateral movement across an organization's network.
Defense Evasion:
Obfuscated macros and legitimate-looking templates evade traditional antivirus and endpoint detection solutions, enabling attackers to maintain undetected presence.
How this Technique is Usually Detected
Detection of Office Template Macros involves a combination of endpoint monitoring, network analysis, and behavioral analytics:
Endpoint Detection:
Monitor Office applications for suspicious macro execution, especially from unusual template locations.
Implement endpoint detection and response (EDR) solutions that flag macros performing suspicious behaviors, such as downloading external payloads or executing PowerShell commands.
Monitor file system changes in Office template directories (
%APPDATA%\Microsoft\Templates\,%ProgramFiles%\Microsoft Office\Templates\) for unauthorized template modifications or creations.
Network Detection:
Identify network traffic originating from Office processes (e.g., WINWORD.EXE, EXCEL.EXE, POWERPNT.EXE) connecting to external or unusual IP addresses or URLs.
Inspect HTTP(S) traffic for known malicious template file downloads (e.g.,
.dotm,.xltm,.potm).
Behavioral Analytics:
Employ Security Information and Event Management (SIEM) solutions to correlate macro execution events with suspicious activities, such as process spawning, script execution, or registry modifications.
Detect unusual user behaviors, such as creating documents from rarely-used templates or accessing templates stored in uncommon network locations.
Indicators of Compromise (IoCs):
Presence of suspicious template files (.dotm, .xltm, .potm) in user or shared directories.
Unusual outbound network connections initiated by Office processes.
Registry entries modified by macros for persistence or execution (e.g., Run keys, Scheduled Tasks).
Macro code patterns commonly associated with obfuscation or downloading external payloads.
Why it is Important to Detect This Technique
Early detection of Office Template Macros is critical due to their potential severe impact on organizations:
Initial Access & Compromise:
Malicious macros provide attackers with an easy entry point into corporate networks, potentially leading to widespread compromise.
Early detection can prevent initial footholds, significantly reducing the risk of further exploitation.
Persistence & Long-term Access:
Template macros can establish persistent backdoors, allowing attackers continued access even after initial compromise remediation.
Detecting and removing malicious templates early avoids prolonged attacker presence and reduces remediation costs.
Data Exfiltration & Espionage:
Malicious macros can facilitate data theft by downloading and executing additional payloads designed to exfiltrate sensitive data.
Early detection prevents the unauthorized transfer of sensitive corporate or personal data.
Ransomware & Malware Deployment:
Attackers often use macro-enabled templates to deploy ransomware or other destructive malware, causing operational disruptions and financial losses.
Timely detection minimizes damage, reduces operational downtime, and decreases recovery expenses.
Compliance & Regulatory Risks:
Undetected malicious macros can lead to data breaches, resulting in regulatory fines, reputational damage, and loss of customer trust.
Preventative detection safeguards an organization's compliance posture and brand reputation.
Examples
Real-world incidents and attack scenarios involving Office Template Macros include:
Emotet Malware Campaigns:
Attackers utilized malicious Word templates (.dotm) delivered via phishing emails.
Upon opening, macros executed PowerShell scripts to download Emotet payloads, leading to further infections like TrickBot and Ryuk ransomware.
Impact included significant financial losses, operational downtime, and sensitive data exfiltration.
APT32 (OceanLotus) Attacks:
APT32 leveraged malicious Excel template files (.xltm) hosted on compromised websites and internal networks.
Macros executed scripts to establish persistence, conduct espionage activities, and exfiltrate sensitive corporate and government data.
Victims included government agencies, multinational corporations, and critical infrastructure sectors.
TA551 (Shathak) Threat Actor:
Utilized malicious PowerPoint templates (.potm) distributed via targeted phishing campaigns.
Macros executed embedded scripts to download and install malware payloads, enabling attackers to gain persistent access and lateral movement capabilities within victim networks.
Resulted in unauthorized access, data theft, and potential deployment of ransomware.
FIN7 Group Attacks:
FIN7 leveraged macro-enabled templates to infiltrate retail, hospitality, and financial services organizations.
Malicious macros executed scripts to download payloads, establish backdoors, and exfiltrate payment card data.
Impact included significant financial fraud, regulatory penalties, and reputational damage.
These examples highlight the versatility, effectiveness, and serious consequences associated with Office Template Macros, underscoring the importance of robust detection and mitigation strategies.
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