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mukul975
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Complete skill folder anatomy across all cybersecurity skills: - scripts/agent.py: 80-150 line Python agents using real libraries (impacket, boto3, azure-mgmt-*, kubernetes, pefile, yara, scapy, shodan, stix2, etc.) - references/api-reference.md: real API documentation with method signatures - LICENSE: MIT license for all skill folders
99 lines
2.0 KiB
Markdown
99 lines
2.0 KiB
Markdown
# Fail2ban Port Scan Detection API Reference
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## fail2ban-client CLI
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```bash
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# Service status
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fail2ban-client status
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# Jail status
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fail2ban-client status sshd
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# Ban IP manually
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fail2ban-client set sshd banip 192.168.1.100
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# Unban IP
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fail2ban-client set sshd unbanip 192.168.1.100
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# Reload configuration
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fail2ban-client reload
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# Get ban time for jail
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fail2ban-client get sshd bantime
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# Set ban time
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fail2ban-client set sshd bantime 7200
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```
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## Jail Configuration (/etc/fail2ban/jail.local)
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```ini
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[DEFAULT]
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bantime = 3600
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findtime = 600
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maxretry = 5
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banaction = iptables-multiport
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[sshd]
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enabled = true
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port = ssh
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filter = sshd
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logpath = /var/log/auth.log
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maxretry = 3
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bantime = 3600
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[portscan]
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enabled = true
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filter = portscan
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logpath = /var/log/syslog
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maxretry = 3
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findtime = 300
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bantime = 86400
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action = iptables-allports[name=portscan]
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```
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## Custom Filter (/etc/fail2ban/filter.d/portscan.conf)
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```ini
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[Definition]
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failregex = UFW BLOCK .* SRC=<HOST>
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iptables .* SRC=<HOST> .* DPT=
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ignoreregex =
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```
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## Ban Actions
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| Action | Description |
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|--------|-------------|
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| `iptables-multiport` | Ban specific ports via iptables |
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| `iptables-allports` | Ban all ports via iptables |
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| `nftables-multiport` | Ban via nftables |
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| `firewallcmd-rich-rules` | Ban via firewalld |
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| `sendmail-whois` | Email notification with WHOIS |
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| `abuseipdb` | Report to AbuseIPDB |
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## Log Parsing Patterns
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```bash
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# Fail2ban log - count bans per IP
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grep "Ban " /var/log/fail2ban.log | grep -oP '\d+\.\d+\.\d+\.\d+' | sort | uniq -c | sort -rn
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# Auth.log - failed SSH logins
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grep "Failed password" /var/log/auth.log | grep -oP 'from \K\d+\.\d+\.\d+\.\d+' | sort | uniq -c | sort -rn
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# Syslog - blocked connections (UFW)
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grep "UFW BLOCK" /var/log/syslog | grep -oP 'SRC=\K\d+\.\d+\.\d+\.\d+' | sort | uniq -c | sort -rn
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```
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## Escalating Ban Times (recidive jail)
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```ini
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[recidive]
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enabled = true
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filter = recidive
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logpath = /var/log/fail2ban.log
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bantime = 604800 # 1 week for repeat offenders
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findtime = 86400
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maxretry = 3
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```
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