ID | Technique | Tactic |
---|---|---|
T1566.001 | Spearphishing Attachment | Initial Access |
T1566 | Phishing | Initial Access |
Detection: Gsuite Suspicious Shared File Name
Description
The following analytic detects shared files in Google Drive with suspicious filenames commonly used in spear phishing campaigns. It leverages GSuite Drive logs to identify documents with titles that include keywords like "dhl," "ups," "invoice," and "shipment." This activity is significant because such filenames are often used to lure users into opening malicious documents or clicking harmful links. If confirmed malicious, this activity could lead to unauthorized access, data theft, or further compromise of the user's system.
Search
1`gsuite_drive` parameters.owner_is_team_drive=false "parameters.doc_title" IN ("*dhl*", "* ups *", "*delivery*", "*parcel*", "*label*", "*invoice*", "*postal*", "*fedex*", "* usps *", "* express *", "*shipment*", "*Banking/Tax*","*shipment*", "*new order*") parameters.doc_type IN ("document","pdf", "msexcel", "msword", "spreadsheet", "presentation")
2| rex field=parameters.owner "[^@]+@(?<source_domain>[^@]+)"
3| rex field=parameters.target_user "[^@]+@(?<dest_domain>[^@]+)"
4| where not source_domain="internal_test_email.com" and dest_domain="internal_test_email.com"
5| eval phase="plan"
6| eval severity="low"
7| stats count min(_time) as firstTime max(_time) as lastTime by email parameters.owner parameters.target_user parameters.doc_title parameters.doc_type phase severity
8| rename parameters.target_user AS user
9| `security_content_ctime(firstTime)`
10| `security_content_ctime(lastTime)`
11| `gsuite_suspicious_shared_file_name_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
G Suite Drive | N/A | 'gsuite:drive:json' |
'http:gsuite' |
N/A |
Macros Used
Name | Value |
---|---|
gsuite_drive | sourcetype=gsuite:drive:json |
gsuite_suspicious_shared_file_name_filter | search * |
gsuite_suspicious_shared_file_name_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Risk Event | True |
Implementation
To successfully implement this search, you need to be ingesting logs related to gsuite having the file attachment metadata like file type, file extension, source email, destination email, num of attachment and etc. In order for the search to work for your environment, please edit the query to use your company specific email domain instead of internal_test_email.com
.
Known False Positives
normal user or normal transaction may contain the subject and file type attachment that this detection try to search
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
suspicious share gdrive from $parameters.owner$ to $email$ namely as $parameters.doc_title$ | 21 | 30 | 70 |
References
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | http:gsuite |
gsuite:drive:json |
Integration | ✅ Passing | Dataset | http:gsuite |
gsuite:drive:json |
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: 2