Detection: Office Document Executing Macro Code

REMOVED DETECTION

This detection has been removed from the Splunk Threat Research content library and is no longer maintained or supported.

Reason: Renamed and updated logic

Removed in version: 5.2.0

Replacement: Windows Office Product Loading VBE7 DLL

If you have any questions or concerns, please reach out to us at research@splunk.com.

Description

The following analytic has been deprecated. The following analytic identifies office documents executing macro code. It leverages Sysmon EventCode 7 to detect when processes like WINWORD.EXE or EXCEL.EXE load specific DLLs associated with macros (e.g., VBE7.DLL). This activity is significant because macros are a common attack vector for delivering malicious payloads, such as malware. If confirmed malicious, this could lead to unauthorized code execution, data exfiltration, or further compromise of the system. Disabling macros by default is recommended to mitigate this risk.

1`sysmon` EventCode=7 process_name IN ("WINWORD.EXE", "EXCEL.EXE", "POWERPNT.EXE","onenote.exe","onenotem.exe","onenoteviewer.exe","onenoteim.exe","msaccess.exe") loaded_file_path IN ("*\\VBE7INTL.DLL","*\\VBE7.DLL", "*\\VBEUI.DLL") 
2| fillnull 
3| stats count min(_time) as firstTime max(_time) as lastTime by EventID FileVersion Guid Hashes Image ImageLoaded MD5 Opcode OriginalFileName ProcessGuid ProcessID ProcessId SHA256 SecurityID Signature SignatureStatus Signed UserID dest loaded_file loaded_file_path original_file_name process_exec process_guid process_hash process_id process_name process_path service_dll_signature_exists service_dll_signature_verified signature signature_id user_id vendor_product 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `office_document_executing_macro_code_filter`

Data Source

Name Platform Sourcetype Source
Sysmon EventID 7 Windows icon Windows 'XmlWinEventLog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Name Value
sysmon (source=WinEventLog:Microsoft-Windows-Sysmon/Operational OR source=XmlWinEventLog:Microsoft-Windows-Sysmon/Operational OR source=Syslog:Linux-Sysmon/Operational)
office_document_executing_macro_code_filter ``
office_document_executing_macro_code_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1566.001 Spearphishing Attachment Initial Access

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule N/A
Earliest Time N/A
Latest Time N/A
Schedule Window N/A
Creates Finding (Notable) No
Creates Intermediate Finding (Risk Event) No
TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

To successfully implement this search, you need to be ingesting logs with the process name and ImageLoaded (Like sysmon EventCode 7) from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Also be sure to include those monitored dll to your own sysmon config.

Known False Positives

False positives may occur if legitimate office documents are executing macro code. Ensure to investigate the macro code and the command to be executed. If the macro code is benign, add the document name to the exclusion list. Some applications may legitimately load VBE7INTL.DLL, VBE7.DLL, or VBEUI.DLL.

Associated Analytic Story

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit Not Applicable N/A N/A N/A
Integration Not Applicable N/A N/A N/A

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range


Source: GitHub |

Version: 11