Complete inventory of all certificates as a basis for migration.

#!/bin/bash
# cert-inventory-linux.sh
 
OUTPUT="inventory-linux-$(hostname)-$(date +%Y%m%d).csv"
echo "Path,Subject,Issuer,Algorithm,KeyLength,ValidFrom,ValidTo,DaysRemaining,Serial,SANs" > "$OUTPUT"
 
# Standard directories
CERT_DIRS=(
    "/etc/ssl/certs"
    "/etc/pki/tls/certs"
    "/etc/nginx/ssl"
    "/etc/apache2/ssl"
    "/opt/*/ssl"
    "/var/lib/docker/volumes/*/ssl"
)
 
for dir in "${CERT_DIRS[@]}"; do
    for cert in $(find $dir -name "*.pem" -o -name "*.crt" -o -name "*.cer" 2>/dev/null); do
        # Only certificates (no keys/CSRs)
        openssl x509 -in "$cert" -noout 2>/dev/null || continue
 
        subject=$(openssl x509 -in "$cert" -subject -noout | sed 's/subject=//' | tr ',' ';')
        issuer=$(openssl x509 -in "$cert" -issuer -noout | sed 's/issuer=//' | tr ',' ';')
        algo=$(openssl x509 -in "$cert" -text -noout | grep "Signature Algorithm" | head -1 | awk '{print $3}')
        keysize=$(openssl x509 -in "$cert" -text -noout | grep "Public-Key:" | grep -oP '\d+')
        not_before=$(openssl x509 -in "$cert" -startdate -noout | cut -d= -f2)
        not_after=$(openssl x509 -in "$cert" -enddate -noout | cut -d= -f2)
        days_left=$(( ($(date -d "$not_after" +%s) - $(date +%s)) / 86400 ))
        serial=$(openssl x509 -in "$cert" -serial -noout | cut -d= -f2)
        sans=$(openssl x509 -in "$cert" -text -noout | grep -A1 "Subject Alternative Name" | tail -1 | tr ',' ';')
 
        echo "\"$cert\",\"$subject\",\"$issuer\",\"$algo\",\"$keysize\",\"$not_before\",\"$not_after\",\"$days_left\",\"$serial\",\"$sans\"" >> "$OUTPUT"
    done
done
 
echo "Inventory completed: $OUTPUT"
echo "Certificates found: $(tail -n +2 "$OUTPUT" | wc -l)"

# Cert-Inventory-Windows.ps1
 
param(
    [string]$OutputPath = "inventory-windows-$env:COMPUTERNAME-$(Get-Date -Format 'yyyyMMdd').csv"
)
 
$results = @()
 
# Search all certificate stores
$stores = @(
    @{ Location = "LocalMachine"; Name = "My" },
    @{ Location = "LocalMachine"; Name = "Root" },
    @{ Location = "LocalMachine"; Name = "CA" },
    @{ Location = "LocalMachine"; Name = "WebHosting" },
    @{ Location = "CurrentUser"; Name = "My" }
)
 
foreach ($store in $stores) {
    $storePath = "Cert:\$($store.Location)\$($store.Name)"
 
    Get-ChildItem $storePath -ErrorAction SilentlyContinue | ForEach-Object {
        $cert = $_
        $daysLeft = ($cert.NotAfter - (Get-Date)).Days
 
        # Extract SANs
        $sanExt = $cert.Extensions | Where-Object { $_.Oid.Value -eq "2.5.29.17" }
        $sans = if ($sanExt) { $sanExt.Format($false) } else { "" }
 
        $results += [PSCustomObject]@{
            Store = "$($store.Location)\$($store.Name)"
            Subject = $cert.Subject
            Issuer = $cert.Issuer
            Algorithm = $cert.SignatureAlgorithm.FriendlyName
            KeySize = $cert.PublicKey.Key.KeySize
            NotBefore = $cert.NotBefore
            NotAfter = $cert.NotAfter
            DaysLeft = $daysLeft
            Serial = $cert.SerialNumber
            Thumbprint = $cert.Thumbprint
            SANs = $sans
            HasPrivateKey = $cert.HasPrivateKey
        }
    }
}
 
$results | Export-Csv -Path $OutputPath -NoTypeInformation -Encoding UTF8
Write-Host "Inventory completed: $OutputPath"
Write-Host "Certificates found: $($results.Count)"

#!/bin/bash
# cert-inventory-network.sh
 
OUTPUT="inventory-network-$(date +%Y%m%d).csv"
ENDPOINTS_FILE="endpoints.txt"
 
echo "Endpoint,Subject,Issuer,Algorithm,KeyLength,ValidTo,Days,Serial" > "$OUTPUT"
 
# Endpoints from file or CMDB/DNS
# Format: hostname:port
cat "$ENDPOINTS_FILE" | while read endpoint; do
    host=${endpoint%:*}
    port=${endpoint#*:}
    [ -z "$port" ] && port=443
 
    echo "Scanning $host:$port..."
 
    cert_info=$(echo | openssl s_client -connect "$host:$port" -servername "$host" 2>/dev/null | openssl x509 -text -noout 2>/dev/null)
 
    if [ -n "$cert_info" ]; then
        subject=$(echo "$cert_info" | grep "Subject:" | head -1 | sed 's/.*Subject: //' | tr ',' ';')
        issuer=$(echo "$cert_info" | grep "Issuer:" | head -1 | sed 's/.*Issuer: //' | tr ',' ';')
        algo=$(echo "$cert_info" | grep "Signature Algorithm" | head -1 | awk '{print $3}')
        keysize=$(echo "$cert_info" | grep "Public-Key:" | grep -oP '\d+')
        not_after=$(echo | openssl s_client -connect "$host:$port" -servername "$host" 2>/dev/null | openssl x509 -enddate -noout | cut -d= -f2)
        days_left=$(( ($(date -d "$not_after" +%s) - $(date +%s)) / 86400 ))
        serial=$(echo | openssl s_client -connect "$host:$port" -servername "$host" 2>/dev/null | openssl x509 -serial -noout | cut -d= -f2)
 
        echo "\"$endpoint\",\"$subject\",\"$issuer\",\"$algo\",\"$keysize\",\"$not_after\",\"$days_left\",\"$serial\"" >> "$OUTPUT"
    else
        echo "\"$endpoint\",\"CONNECTION FAILED\",\"\",\"\",\"\",\"\",\"\",\"\"" >> "$OUTPUT"
    fi
done
 
echo "Network inventory completed: $OUTPUT"

#!/bin/bash
# cert-inventory-ca.sh - From OpenSSL CA index
 
CA_INDEX="/etc/pki/CA/index.txt"
OUTPUT="inventory-ca-$(date +%Y%m%d).csv"
 
echo "Status,Serial,Expiry,Subject,File" > "$OUTPUT"
 
while IFS=$'\t' read -r status expiry revoke serial unknown subject; do
    # Status: V=Valid, R=Revoked, E=Expired
    status_text=""
    case "$status" in
        V) status_text="Valid" ;;
        R) status_text="Revoked" ;;
        E) status_text="Expired" ;;
    esac
 
    # Convert expiry date (YYMMDDHHMMSSZ format)
    expiry_formatted=$(date -d "20${expiry:0:2}-${expiry:2:2}-${expiry:4:2}" +%Y-%m-%d 2>/dev/null)
 
    # Certificate file
    cert_file="/etc/pki/CA/newcerts/${serial}.pem"
 
    echo "\"$status_text\",\"$serial\",\"$expiry_formatted\",\"$subject\",\"$cert_file\"" >> "$OUTPUT"
done < "$CA_INDEX"
 
echo "CA inventory completed: $OUTPUT"
echo "Certificates:"
echo "  Valid:   $(grep -c "^\"Valid\"" "$OUTPUT")"
echo "  Revoked: $(grep -c "^\"Revoked\"" "$OUTPUT")"
echo "  Expired: $(grep -c "^\"Expired\"" "$OUTPUT")"

#!/usr/bin/env python3
# analyze-inventory.py
 
import pandas as pd
from datetime import datetime
 
# Load all inventory files
df = pd.concat([
    pd.read_csv('inventory-linux*.csv'),
    pd.read_csv('inventory-windows*.csv'),
    pd.read_csv('inventory-network*.csv')
])
 
# Analysis
print("=== Inventory Summary ===\n")
 
print(f"Total certificates: {len(df)}")
 
print("\n--- By Algorithm ---")
print(df['Algorithm'].value_counts())
 
print("\n--- By Key Length ---")
print(df['KeyLength'].value_counts())
 
print("\n--- Expiry Analysis ---")
df['DaysRemaining'] = pd.to_numeric(df['DaysRemaining'], errors='coerce')
print(f"Expired:          {len(df[df['DaysRemaining'] < 0])}")
print(f"< 30 days:        {len(df[(df['DaysRemaining'] >= 0) & (df['DaysRemaining'] < 30)])}")
print(f"30-90 days:       {len(df[(df['DaysRemaining'] >= 30) & (df['DaysRemaining'] < 90)])}")
print(f"90-365 days:      {len(df[(df['DaysRemaining'] >= 90) & (df['DaysRemaining'] < 365)])}")
print(f"> 1 year:         {len(df[df['DaysRemaining'] >= 365])}")
 
print("\n--- Migration Potential ---")
rsa = len(df[df['Algorithm'].str.contains('rsa', case=False, na=False)])
ecdsa = len(df[df['Algorithm'].str.contains('ecdsa|ec', case=False, na=False)])
hybrid = len(df[df['Algorithm'].str.contains('ml-dsa|hybrid', case=False, na=False)])
print(f"RSA (to migrate):     {rsa}")
print(f"ECDSA (to migrate):   {ecdsa}")
print(f"Hybrid (already):     {hybrid}")
 
# Export for migration planning
df.to_excel('inventory-complete.xlsx', index=False)
print("\nComplete inventory exported: inventory-complete.xlsx")

• Classic -> Hybrid - Start migration
• Expiry Monitoring - Ongoing monitoring
• Business - Strategic planning

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Wolfgang van der Stille @ EMSR DATA d.o.o. - Post-Quantum Cryptography Professional