Detection: LOLBAS With Network Traffic

Description

The following analytic identifies the use of Living Off the Land Binaries and Scripts (LOLBAS) with network traffic. It leverages data from the Network Traffic data model to detect when native Windows binaries, often abused by adversaries, initiate network connections. This activity is significant as LOLBAS are frequently used to download malicious payloads, enabling lateral movement, command-and-control, or data exfiltration. If confirmed malicious, this behavior could allow attackers to execute arbitrary code, escalate privileges, or maintain persistence within the environment, posing a severe threat to organizational security.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Network_Traffic.All_Traffic where (All_Traffic.app IN ("*Regsvcs.exe", "*\\Ftp.exe", "*OfflineScannerShell.exe", "*Rasautou.exe", "*Schtasks.exe", "*Xwizard.exe", "*Pnputil.exe", "*Atbroker.exe", "*Pcwrun.exe", "*Ttdinject.exe", "*Mshta.exe", "*Bitsadmin.exe", "*Certoc.exe", "*Ieexec.exe", "*Microsoft.Workflow.Compiler.exe", "*Runscripthelper.exe", "*Forfiles.exe", "*Msbuild.exe", "*Register-cimprovider.exe", "*Tttracer.exe", "*Ie4uinit.exe", "*Bash.exe", "*Hh.exe", "*SettingSyncHost.exe", "*Cmstp.exe", "*Stordiag.exe", "*Scriptrunner.exe", "*Odbcconf.exe", "*Extexport.exe", "*Msdt.exe", "*WorkFolders.exe", "*Diskshadow.exe", "*Mavinject.exe", "*Regasm.exe", "*Gpscript.exe", "*Regsvr32.exe", "*Msiexec.exe", "*Wuauclt.exe", "*Presentationhost.exe", "*Wmic.exe", "*Runonce.exe", "*Syncappvpublishingserver.exe", "*Verclsid.exe", "*Infdefaultinstall.exe", "*Installutil.exe", "*Netsh.exe", "*Wab.exe", "*Dnscmd.exe", "*\\At.exe", "*Pcalua.exe", "*Msconfig.exe", "*makecab.exe", "*cscript.exe", "*notepad.exe", "*\\cmd.exe", "*certutil.exe", "*\\powershell.exe", "*powershell_ise.exe")) by All_Traffic.app,All_Traffic.src,All_Traffic.src_ip,All_Traffic.user,All_Traffic.dest,All_Traffic.dest_ip 
3| `drop_dm_object_name(All_Traffic)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| rex field=app ".*\\\(?<process_name>.*)$" 
7| rename app as process 
8| `lolbas_with_network_traffic_filter`

Data Source

Name Platform Sourcetype Source Supported App
Sysmon EventID 3 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
lolbas_with_network_traffic_filter search *
lolbas_with_network_traffic_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1105 Ingress Tool Transfer Command And Control
T1567 Exfiltration Over Web Service Exfiltration
T1218 System Binary Proxy Execution Defense Evasion
KillChainPhase.ACTIONS_ON_OBJECTIVES
KillChainPhase.COMMAND_AND_CONTROL
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_13
APT-C-36
APT18
APT28
APT29
APT3
APT32
APT33
APT37
APT38
APT39
APT41
Ajax Security Team
Andariel
Aquatic Panda
BITTER
BRONZE BUTLER
BackdoorDiplomacy
Chimera
Cinnamon Tempest
Cobalt Group
Confucius
Darkhotel
Dragonfly
Elderwood
Ember Bear
Evilnum
FIN13
FIN7
FIN8
Fox Kitten
GALLIUM
Gamaredon Group
Gorgon Group
HAFNIUM
HEXANE
IndigoZebra
Indrik Spider
Ke3chang
Kimsuky
Lazarus Group
LazyScripter
Leviathan
LuminousMoth
Magic Hound
Metador
Molerats
Moses Staff
MuddyWater
Mustang Panda
Mustard Tempest
Nomadic Octopus
OilRig
PLATINUM
Patchwork
Rancor
Rocke
Sandworm Team
SideCopy
Sidewinder
Silence
TA2541
TA505
TA551
TeamTNT
Threat Group-3390
Tonto Team
Tropic Trooper
Turla
Volatile Cedar
WIRTE
Whitefly
Windshift
Winnti Group
Wizard Spider
ZIRCONIUM
menuPass
APT28
Magic Hound
Lazarus Group

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 Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this detection you must ingest events into the Network traffic data model that contain the source, destination, and communicating process in the app feild. Relevant processes must also be ingested in the Endpoint data model with matching process_id feild. Sysmon EID1 and EID3 are good examples of this type this data type.

Known False Positives

Legitmate usage of internal automation or scripting, espically powershell.exe internal to internal or logon scripts. It may be necessary to omit internal IP ranges if extremely noisy. ie NOT dest_ip IN ("10.0.0.0/8","172.16.0.0/12","192.168.0.0/16","170.98.0.0/16","0:0:0:0:0:0:0:1")

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
The LOLBAS $process_name$ on device $src$ was seen communicating with $dest$. 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Passing N/A N/A N/A
Unit Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational xmlwineventlog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational xmlwineventlog

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: 3