Detection rules › Splunk
DNX.exe Proxy Execution (Windows Event Log)
dnx.exe is a .Net Execution environment file included with .Net. It is possible for adversaries to launch unsigned code with dnx.exe
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth |
References
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Security-Auditing | Event ID 4688: A new process has been created. |
Rule body
id: '6564.7498'
title: DNX.exe Proxy Execution
description: dnx.exe is a .Net Execution environment file included with .Net. It is
possible for adversaries to launch unsigned code with dnx.exe. Living Off the Land
Binary and Scripts (LOLBAS) (LOLBIN)
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
"<EventID>4688<") "Dnx.EXE" | table _time, host, user user, process, process_*,
parent_* | bin span=1s | stats values(*) as * by _time, host '
techniques:
- defense-evasion:system binary proxy execution
technique_id:
- T1218
data_category:
- Windows event logs
references:
- https://lolbas-project.github.io/lolbas/OtherMSBinaries/Dnx/
- https://enigma0x3.net/2016/11/17/bypassing-application-whitelisting-by-using-dnx-exe/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<") "Dnx.EXE"
Stage 2: table
| table _time, host, user user, process, process_*, parent_*
Stage 3: bucket
| bin span=1s
Stage 4: stats
| stats values(*) as * by _time, host
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
EventCode | eq |
| field:"EventID" kind:eq value:"4688" |
Search terms
These SPL tokens match against raw event text.
| Stage | Term |
|---|---|
| 1 | "<EventID>4688<" |
| 1 | "Dnx.EXE" |