Mega Utility Execution - Windows (Windows Event Log)

Group by: _time, host
Source: github.com/anvilogic-forge/armory

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

Telemetry coverage

Provider	Record / event type
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

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

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`EventCode`	eq	`4688` corpus 317 (splunk 283, kusto 33, elastic 1)	`field:"EventID" kind:eq value:"4688"`
`process_name`	regex_match	`"(?i)megasync.exe` `megacmd"` corpus 2 (splunk 2)	`field:"process_name" kind:regex_match`

Search terms

These SPL tokens match against raw event text.

Stage	Term
1	`"<EventID>4688<"`
1	`"Megasync.exe"`
1	`"megacmd"`