Gsuite Suspicious Shared File Name
This search is to detect a shared file in google drive with suspicious file name that are commonly used by spear phishing campaign. This technique is very popular to lure the user by running a malicious document or click a malicious link within the shared file that will redirected to malicious website. This detection can also catch some normal email communication between organization and its external customer.
- Type: Anomaly
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2021-08-23
- Author: Teoderick Contreras, Splunk
- ID: 07eed200-03f5-11ec-98fb-acde48001122
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 7 8 9 10 11 `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") | rex field=parameters.owner "[^@]+@(?<source_domain>[^@]+)" | rex field=parameters.target_user "[^@]+@(?<dest_domain>[^@]+)" | where not source_domain="internal_test_email.com" and dest_domain="internal_test_email.com" | eval phase="plan" | eval severity="low" | 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 | rename parameters.target_user AS user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `gsuite_suspicious_shared_file_name_filter`
The SPL above uses the following Macros:
gsuite_suspicious_shared_file_name_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
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
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
|21.0||30||70||suspicious share gdrive from $parameters.owner$ to $email$ namely as $parameters.doc_title$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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source | version: 1