---
title: "NET-DB-013 Mail Cleartext Authentication Allowed"
canonical: https://openvapt.com/checks/NET-DB-013.html
html: https://openvapt.com/checks/NET-DB-013.html
site: OpenVAPT, https://openvapt.com/
license: OpenVAPT Source-Available Licence 1.3, https://openvapt.com/legal/licence-text.html
modified: 2026-10-14
version: 0.1.0-alpha.6
---

# NET-DB-013 Mail Cleartext Authentication Allowed

Postfix or Dovecot permits plaintext authentication without requiring TLS.

- Domain: Network
- Severity: Medium
- Control category: Cryptography and TLS
- Fix effort: low
- CVSS v3.1 vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N`
- CIS Controls v8: 3.10
- NIST CSF 2.0: PR.DS-02
- CWE: CWE-319, CWE-523
- OWASP Top 10 2021: A02:2021
- OWASP ASVS 4.0.3: 9.1.1
- NIST SP 800-53 Rev. 5: SC-8, IA-5(1)
- Benchmark topic: Secure data service configuration (topic only, no benchmark text)

## Why It Matters

Credentials sent before transport encryption can be observed by any party able to intercept the connection.

## How It Detects

Reads Postfix smtpd_tls_auth_only and Dovecot disable_plaintext_auth, and flags no values.

## How to Fix

Set smtpd_tls_auth_only = yes and disable_plaintext_auth = yes. Use implicit TLS on ports 465, 993, and 995. STARTTLS assessment is out of scope.

## How to Verify

```
Confirm the effective mail configuration and that unauthenticated plaintext sessions do not advertise AUTH.
```

## Learn the Theory

- [P3 Network Exposure and Firewalls](https://openvapt.com/academy/p3.md)
- [P8 Data Services: Databases, File Shares, DNS and Mail](https://openvapt.com/academy/p8.md)

## References

- [Dovecot Authentication Settings](https://doc.dovecot.org/main/core/config/auth/settings.html)

## Source Code

https://github.com/OpenVAPT/openvapt/blob/574f7f3333c44b75a3c649e2d93a76d507f75adf/internal/checks/network/services.go

Run it: `openvapt scan --only NET-DB-013`. Read it offline: `openvapt explain NET-DB-013`.

---

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