ログソース：OS、ネットワーク、アプリケーションのログ

# View Windows Event Logs
# Event Viewer (GUI): eventvwr.msc

# PowerShell
Get-EventLog -LogName Security -Newest 50
Get-WinEvent -LogName Security | Where-Object {$_.Id -eq 4625}

# Key Security Event IDs:
# 4624: Logon success
# 4625: Logon failure
# 4648: Explicit credentials
# 4672: Admin logon

# View auth log
tail -f /var/log/auth.log

# Search for failed SSH logins
grep "Failed password" /var/log/auth.log

# Systemd journal
journalctl -u sshd -f
journalctl --since "1 hour ago"
journalctl -p err -b

# Apache format:
# IP - - [timestamp] "METHOD /path HTTP/1.1" status bytes "referer" "UA"
192.168.1.50 - - [01/Jan/2025:10:23:45 +0000] "GET /admin HTTP/1.1" 403 287

# Find 4xx errors (potential scanning)
grep " 40[0-9] " /var/log/apache2/access.log | awk '{print $1}' | sort | uniq -c | sort -rn

# iptables logging rule
iptables -A INPUT -j LOG --log-prefix "IPTABLES-DENY: "

# View firewall logs
grep "IPTABLES-DENY" /var/log/syslog

# Palo Alto/Cisco ASA logs go to syslog
# Format: date, action, src, dst, port, bytes

# Enable query logging in BIND
# named.conf:
logging {
    channel query_log {
        file "/var/log/named/queries.log";
        severity info;
        print-time yes;
    };
    category queries { query_log; };
};

# Detect tunneling: long subdomains
awk '{print length($0), $0}' queries.log | sort -rn | head -20

# DHCP log location (Linux):
/var/log/dhcpd.log
/var/lib/dhcpd/dhcpd.leases

# Windows DHCP Server:
# C:\Windows\System32\dhcp\DhcpSrvLog-*.log

# Correlate: IP address → MAC → hostname → user

# MySQL query log
# my.cnf:
general_log = 1
general_log_file = /var/log/mysql/query.log

# PostgreSQL
# postgresql.conf:
log_statement = 'all'
log_min_duration_statement = 0

# View slow queries
grep "Query" /var/log/mysql/query.log | grep -v "SELECT 1"