Detection rules › Splunk
Mega Utility Execution - Windows (Windows Event Log)
Mega is a cloud storage service used by many threat actors due to its use of end-to-end encryption and semi-anonymous payment options. The client application MEGAsync.exe and command-line interface utility MegaCMD allow threat actors to exfiltrate large amounts of data. This use case detects process executions of MEGASync or MegaCMD.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Exfiltration | T1567 Exfiltration Over Web Service |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body yaml
id: '35820.62790'
title: Mega Utility Execution - Windows
description: Mega is a cloud storage service used by many threat actors due to its
use of end-to-end encryption and semi-anonymous payment options. The client application
MEGAsync.exe and command-line interface utility MegaCMD allow threat actors to exfiltrate
large amounts of data. This use case detects process executions of MEGASync or MegaCMD.
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
"<EventID>4688<" OR Type=Process) "Megasync.exe" OR "megacmd" | regex process_name="(?i)megasync\.exe|megacmd"
| table _time, host, user process, process_*, parent_* | bin span=1s | stats values(*)
as * by _time, host '
techniques:
- exfiltration:exfiltration over web service
technique_id:
- T1567
data_category:
- Windows event logs
references:
- https://redcanary.com/blog/threat-detection/rclone-mega-extortion/
- https://mega.io/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) "Megasync.exe" OR "megacmd"
Stage 2: regex
| regex process_name="(?i)megasync\.exe|megacmd"
Stage 3: table
| table _time, host, user process, process_*, parent_*
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
process_name | regex_match |
|
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>4688<" |
| 1 | "Megasync.exe" |
| 1 | "megacmd" |