splunk-security_content/docs/_posts/2021-04-14-office_document_executing_macro_code.md

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title	excerpt	categories	last_modified_at	toc	toc_label	tags
Office Document Executing Macro Code	Phishing , Spearphishing Attachment	Endpoint	2021-04-14	true		Phishing Spearphishing Attachment Initial Access Initial Access Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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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
• Datamodel: Endpoint
• Last Updated: 2021-04-14
• Author: Teoderick Contreras, Splunk
• ID: b12c89bc-9d06-11eb-a592-acde48001122

Annotations

ATT&CK

ID	Technique	Tactic
T1566	Phishing	Initial Access

| T1566.001 | Spearphishing Attachment | Initial Access |

Kill Chain Phase

• Exploitation

NIST

CIS20

CVE

Search

`sysmon` EventCode=7 parent_process_name IN ("WINWORD.EXE", "EXCEL.EXE", "POWERPNT.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 
| `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

ℹ️ 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 field

• ImageLoaded
• AllImageLoaded
• Computer
• 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

RBA

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

ℹ️ 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

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566.001/datasets/windows-sysmon.log

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