---
title: "NET-DB-018 MySQL Resolves Client Host Names"
canonical: https://openvapt.com/checks/NET-DB-018.html
html: https://openvapt.com/checks/NET-DB-018.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-018 MySQL Resolves Client Host Names

skip-name-resolve is not set, so grants that name hosts depend on DNS answers and every connection waits on a reverse lookup.

- Domain: Network
- Severity: Low
- Control category: Data Services
- Fix effort: low
- CVSS v3.1 vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N`
- CIS Controls v8: 4.1
- NIST CSF 2.0: PR.PS-01
- CWE: CWE-350, CWE-290
- OWASP Top 10 2021: A05:2021
- OWASP ASVS 4.0.3: 14.1.3
- NIST SP 800-53 Rev. 5: CM-6, IA-3
- Benchmark topic: Database server hardening (topic only, no benchmark text)

## Why It Matters

Host-based grants that trust names can be satisfied by whoever controls DNS or the resolver path. With skip-name-resolve the server matches IP addresses only, which is both faster and not spoofable through DNS. Grants that use host names must be rewritten first.

## How It Detects

Parses the option files for skip-name-resolve, skip_name_resolve or host_cache_size=0 under [mysqld]. Fails when none is present.

## How to Fix

Rewrite grants that use host names to IP addresses or '%', then add  skip-name-resolve  under [mysqld] and restart in a maintenance window.

## How to Verify

```
SHOW VARIABLES LIKE 'skip_name_resolve';  should print ON.
```

## 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)
- [P19 Database, Mail and DNS Hardening](https://openvapt.com/academy/p19.md)

## References

- [MySQL 8.4 Reference Manual, skip_name_resolve](https://dev.mysql.com/doc/refman/8.4/en/server-system-variables.html#sysvar_skip_name_resolve)
- [MySQL 8.4 Reference Manual, Security Guidelines](https://dev.mysql.com/doc/refman/8.4/en/security-guidelines.html)

## Source Code

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

Run it: `openvapt scan --only NET-DB-018`. Read it offline: `openvapt explain NET-DB-018`.

---

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