PART B: SOC Detection, Hunting & Incident Response Toolkit

1. ASSET DISCOVERY & INVENTORY

PowerShell: `Find-DigieverDevices.ps1`

Parameter Block

param(
    [string]$SubnetRange = "192.168.0.0/16",
    [int]$Timeout = 3000,
    [string]$OutputFile = "digiever_inventory.csv"
)

What this actually means

param() defines runtime inputs for the script
[string] and [int] are strong typing, preventing accidental misuse
Default values allow the script to run without arguments

Why this matters operationally

SOC analysts often copy scripts between jump boxes
Parameters prevent analysts from editing code directly
Reduces risk of accidental misconfiguration during incidents

Function Declaration

function Test-DigieverDevice {

This creates a reusable logical unit. Instead of duplicating detection logic, the script calls this function repeatedly.

SOC best practice:

If logic is reused → it should be a function.

Function Parameters

param(
    [string]$IpAddress,
    [int]$Port = 80
)

$IpAddress → target host under test
$Port → defaults to 80 but allows scanning alternate ports

Why this matters:

Digiever devices often run management interfaces on non-standard ports
Attackers always scan multiple ports — defenders should too

HTTP Probe

$response = Invoke-WebRequest -Uri "http://$IpAddress:$Port/cgi-bin/cgi_main.cgi"

Deep explanation

Invoke-WebRequest simulates a browser request
/cgi-bin/cgi_main.cgi is a known Digiever control endpoint
No credentials are supplied → mirrors attacker behavior

This is passive identification, not exploitation.

Timeout & Error Handling

-TimeoutSec 3 -ErrorAction SilentlyContinue

Prevents the script from hanging on dead hosts
Suppresses noisy errors (timeouts, refused connections)

SOC rationale:

Discovery scripts must fail fast
Noise kills analyst productivity

Response Validation

if ($response.StatusCode -eq 200 -or $response.Content -like "*digiever*")

Two independent checks:

HTTP 200
- Embedded devices often return 200 even when misconfigured
Vendor string
- Some firmware leaks product identifiers

Either condition = probable Digiever device

Export Logic

Export-Csv -NoTypeInformation

Produces a structured CSV
-NoTypeInformation avoids PowerShell metadata

Why CSV?

Easy ingestion into SIEM
Easy correlation with asset inventory
Human-readable during incidents

2. BASH DISCOVERY SCRIPT

Nmap Command

nmap -p 80,8080,443,8443 --open -n -Pn $SUBNET

Flag-by-flag breakdown:

-p → restricts scan to known management ports
--open → suppresses closed ports
-n → skips DNS (faster, quieter)
-Pn → assumes host is alive

Why attackers use this exact pattern:

Speed
Stealth
Efficiency

Defenders mirror attacker methodology to see what attackers see.

Curl CGI Probe

curl -s -I http://$host:$port/cgi-bin/cgi_main.cgi

-s → silent mode
-I → HEAD request (no body)

Why HEAD?

Faster
Less intrusive
Still confirms endpoint existence

3. SNORT RULES

Rule Header

alert tcp $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS

Meaning:

Generate an alert
TCP traffic
From untrusted network → internal web services

This scopes the rule to incoming attack traffic.

Flow Control

flow:to_server,established;

to_server → request direction
established → valid TCP session

Why important:

Eliminates false positives from scans or partial connections

URI Match

http_uri;
content:"/cgi-bin/cgi_main.cgi";

Restricts inspection to the request URI
Confirms Digiever CGI access

Body Inspection

http_client_body;
content:"cgiName=time_tzsetup.cgi";

Switches inspection to POST body
Targets the vulnerable function

This is precision targeting, not generic CGI detection.

Regex Injection Detection

pcre:"/ntp=[0-9a-zA-Z\.\s]*[|`\;]/";

Breakdown:

ntp= → vulnerable parameter
[0-9a-zA-Z\.\s]* → allows legitimate input
[|;]` → shell execution characters

This detects active exploitation, not benign access.

SID & Revision

sid:1000001;
rev:1;

SID in local range → avoids collision with vendor rules
rev tracks tuning changes

4. MICROSOFT SENTINEL (KQL)

Base Table

DeviceNetworkEvents

This table records:

Network connections
URLs
Ports
Directionality

It is the correct telemetry source for CGI exploitation.

Port Filtering

| where RemotePort in (80, 443, 8080, 8443)

Reduces dataset size by ~80% in most environments.

URI Filtering

| where RemoteUrl contains "/cgi-bin/cgi_main.cgi"

This is a high-signal filter — normal user traffic should never hit this.

Injection Detection

| where RemoteUrl has_any ("|", "`", ";", "$", "&")

Shell operators inside URLs are almost never legitimate.

This is behavioral detection, not IOC-based.

Classification Logic

extend InjectionIndicator = case(...)

Why this is powerful:

Converts raw alerts into analyst-friendly context
Reduces investigation time
Improves reporting quality

Aggregation

summarize count(), dcount(RemoteIPAddr)

Single hit → probe
Multiple hits → exploitation

SOC analysts triage faster using aggregation.

5. SQL THREAT HUNTING

Baseline Query

COUNT(DISTINCT Hour) as ActiveHours

Normal admin behavior:

Limited time window
Predictable access patterns

Attack behavior:

Random hours
Sustained attempts

Injection Pattern Detection

URL CONTAINS '$('

This specifically detects command substitution, a strong exploitation indicator.

Failed Authentication Analysis

HTTPStatusCode IN (401, 403)

Why this exists:

Attackers may attempt auth before discovering auth bypass
Helps reconstruct pre-exploitation behavior

6. INCIDENT RESPONSE PLAYBOOK

“Do Not Reboot”

Reason:

Malware often resides in memory or temp directories
Reboot destroys volatile forensic evidence

Isolation Over Shutdown

Why unplugging is preferred:

Prevents C2
Preserves disk state
Stops attacker interaction

Replacement Recommendation

Embedded devices:

Cannot be reliably cleaned
Often lack integrity validation
Are cheap relative to breach cost

Replacement is the only trustworthy recovery.

7. CONTINUOUS MONITORING — WHY THIS WORKS

Cadence Design

Daily → detection assurance
Weekly → trend identification
Monthly → drift correction
Quarterly → strategic review

This mirrors SOC maturity models.