Office Document Executing Macro Code

Try in Splunk Security Cloud

Description

this detection was designed to identifies suspicious office documents that using macro code. Macro code is known to be one of the prevalent weaponization or attack vector of threat actor. This malicious macro code is embed to a office document as an attachment that may execute malicious payload, download malware payload or other malware component. It is really good practice to disable macro by default to avoid automatically execute macro code while opening or closing a office document files.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2023-01-24
• Author: Teoderick Contreras, Splunk
• ID: b12c89bc-9d06-11eb-a592-acde48001122

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1566	Phishing	Initial Access

T1566.001

Spearphishing Attachment

Initial Access

Kill Chain Phase

• Delivery

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

`sysmon` EventCode=7 parent_process_name IN ("WINWORD.EXE", "EXCEL.EXE", "POWERPNT.EXE","onenote.exe","onenotem.exe","onenoteviewer.exe","onenoteim.exe","msaccess.exe") ImageLoaded IN ("*\\VBE7INTL.DLL","*\\VBE7.DLL", "*\\VBEUI.DLL") 
| stats min(_time) as firstTime max(_time) as lastTime values(ImageLoaded) as AllImageLoaded count by Computer EventCode Image process_name ProcessId ProcessGuid 
| rename Computer as dest
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `office_document_executing_macro_code_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• sysmon

office_document_executing_macro_code_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

• ImageLoaded
• AllImageLoaded
• dest
• EventCode
• Image
• process_name
• ProcessId
• ProcessGuid
• _time

How To Implement

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

Normal Office Document macro use for automation

Associated Analytic Story

• Spearphishing Attachments
• Trickbot
• IcedID
• DarkCrystal RAT
• AgentTesla
• Qakbot
• Azorult
• Remcos
• PlugX
• NjRAT

RBA

Risk Score	Impact	Confidence	Message
35.0	70	50	Office document executing a macro on $dest$

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://www.joesandbox.com/analysis/386500/0/html
• https://www.joesandbox.com/analysis/702680/0/html
• https://bazaar.abuse.ch/sample/02cbc1ab80695fc12ff8822b926957c3a600247b9ca412a137f69cb5716c8781/
• https://www.fortinet.com/blog/threat-research/latest-remcos-rat-phishing
• https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/trojanized-onenote-document-leads-to-formbook-malware/
• https://www.fortinet.com/blog/threat-research/leveraging-microsoft-office-documents-to-deliver-agent-tesla-and-njrat

Test Dataset

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 | version: 4