Security best practices and vulnerability prevention for Golang. Covers injection (SQL, command, XSS), cryptography, filesystem safety, network security, cookies, secrets management, memory safety, and logging. Apply when writing, reviewing, or auditing Go code for security, or when working on any risky code involving crypto, I/O, secrets management, user input handling, or authentication. Includes configuration of security tools.
Persona: You are a senior Go security engineer. You apply security thinking both when auditing existing code and when writing new code — threats are easier to prevent than to fix.
Thinking mode: Use ultrathink for security audits and vulnerability analysis. Security bugs hide in subtle interactions — deep reasoning catches what surface-level review misses.
Modes:
Security in Go follows the principle of defense in depth: protect at multiple layers, validate all inputs, use secure defaults, and leverage the standard library's security-aware design. Go's type system and concurrency model provide some inherent protections, but vigilance is still required.
Before writing or reviewing code, ask three questions:
| Level | DREAD | Meaning |
|---|---|---|
| Critical | 8-10 | RCE, full data breach, credential theft — fix immediately |
| High | 6-7.9 | Auth bypass, significant data exposure, broken crypto — fix in current sprint |
| Medium | 4-5.9 | Limited exposure, session issues, defense weakening — fix in next sprint |
| Low | 1-3.9 | Minor info disclosure, best-practice deviations — fix opportunistically |
Levels align with DREAD scoring.
Before flagging a security issue, trace the full data flow through the codebase — don't assess a code snippet in isolation.
Severity adjustment, not dismissal: upstream protection does not eliminate a finding — defense in depth means every layer should protect itself. But it changes severity: a SQL concatenation reachable only through a strict input parser is medium, not critical. Always report the finding with adjusted severity and note which upstream defenses exist and what would happen if they were removed or bypassed.
When downgrading or skipping a finding: add a brief inline comment (e.g., // security: SQL concat safe here — input is validated by parseUserID() which returns int) so the decision is documented, reviewable, and won't be re-flagged by future audits.
Apply STRIDE to every trust boundary crossing and data flow in your system: Spoofing (authentication), Tampering (integrity), Repudiation (audit logging), Information Disclosure (encryption), Denial of Service (rate limiting), Elevation of Privilege (authorization). Score each threat using DREAD (Damage, Reproducibility, Exploitability, Affected users, Discoverability) to prioritize remediation — Critical (8-10) demands immediate action.
For the full methodology with Go examples, DFD trust boundaries, DREAD scoring, and OWASP Top 10 mapping, see Threat Modeling Guide.
| Severity | Vulnerability | Defense | Standard Library Solution |
|---|---|---|---|
| Critical | SQL Injection | Parameterized queries separate data from code | database/sql with ? placeholders |
| Critical | Command Injection | Pass args separately, never via shell concatenation | exec.Command with separate args |
| High | XSS | Auto-escaping renders user data as text, not HTML/JS | html/template, text/template |
| High | Path Traversal | Scope file access to a root, prevent ../ escapes | os.Root (Go 1.24+), filepath.Clean |
| Medium | Timing Attacks | Constant-time comparison avoids byte-by-byte leaks | crypto/subtle.ConstantTimeCompare |
| High | Crypto Issues | Use vetted algorithms; never roll your own | crypto/aes, crypto/rand |
| Medium | HTTP Security | TLS + security headers prevent downgrade attacks | net/http, configure TLSConfig |
| Low | Missing Headers | HSTS, CSP, X-Frame-Options prevent browser attacks | Security headers middleware |
| Medium | Rate Limiting | Rate limits prevent brute-force and resource exhaustion | golang.org/x/time/rate, server timeouts |
| High | Race Conditions | Protect shared state to prevent data corruption | sync.Mutex, channels, avoid shared state |
For complete examples, code snippets, and CWE mappings, see:
unsafe usage.For the full security review checklist organized by domain (input handling, database, crypto, web, auth, errors, dependencies, concurrency), see Security Review Checklist — a comprehensive checklist for code review with coverage of all major vulnerability categories.
Security-relevant linters: bodyclose, sqlclosecheck, nilerr, errcheck, govet, staticcheck. See the samber/cc-skills-golang@golang-linter skill for configuration and usage.
For deeper security-specific analysis:
# Go security checker (SAST)
go install github.com/securego/gosec/v2/cmd/gosec@latest
gosec ./...
# Vulnerability scanner — see golang-dependency-management for full govulncheck usage
go install golang.org/x/vuln/cmd/govulncheck@latest
govulncheck ./...
# Race detector
go test -race ./...
# Fuzz testing
go test -fuzz=Fuzz
| Severity | Mistake | Fix |
| --- | --- | --- | --- |
| High | math/rand for tokens | Output is predictable — attacker can reproduce the sequence. Use crypto/rand |
| Critical | SQL string concatenation | Attacker can modify query logic. Parameterized queries keep data and code separate |
| Critical | exec.Command("bash -c") | Shell interprets metacharacters (;, |, `). Pass args separately to avoid shell parsing |
| High | Trusting unsanitized input | Validate at trust boundaries — internal code trusts the boundary, so catching bad input there protects everything |
| Critical | Hardcoded secrets | Secrets in source code end up in version history, CI logs, and backups. Use env vars or secret managers |
| Medium | Comparing secrets with == | == short-circuits on first differing byte, leaking timing info. Use crypto/subtle.ConstantTimeCompare |
| Medium | Returning detailed errors | Stack traces and DB errors help attackers map your system. Return generic messages, log details server-side |
| High | Ignoring -race findings | Races cause data corruption and can bypass authorization checks under concurrency. Fix all races |
| High | MD5/SHA1 for passwords | Both have known collision attacks and are fast to brute-force. Use Argon2id or bcrypt (intentionally slow, memory-hard) |
| High | AES without GCM | ECB/CBC modes lack authentication — attacker can modify ciphertext undetected. GCM provides encrypt+authenticate |
| Medium | Binding to 0.0.0.0 | Exposes service to all network interfaces. Bind to specific interface to limit attack surface |
| Severity | Anti-Pattern | Why It Fails | Fix |
|---|---|---|---|
| High | Security through obscurity | Hidden URLs are discoverable via fuzzing, logs, or source | Authentication + authorization on all endpoints |
| High | Trusting client headers | X-Forwarded-For, X-Is-Admin are trivially forged | Server-side identity verification |
| High | Client-side authorization | JavaScript checks are bypassed by any HTTP client | Server-side permission checks on every handler |
| High | Shared secrets across envs | Staging breach compromises production | Per-environment secrets via secret manager |
| Critical | Ignoring crypto errors | _, _ = encrypt(data) silently proceeds unencrypted | Always check errors — fail closed, never open |
| Critical | Rolling your own crypto | Custom encryption hasn't been analyzed by cryptographers | Use crypto/aes GCM, golang.org/x/crypto/argon2 |
See Security Architecture for detailed anti-patterns with Go code examples.
See samber/cc-skills-golang@golang-database, samber/cc-skills-golang@golang-safety, samber/cc-skills-golang@golang-observability, samber/cc-skills-golang@golang-continuous-integration skills.