𝗦𝗲𝗰𝘂𝗿𝗶𝘁𝘆 𝗔𝘂𝗱𝗶𝘁 𝗥𝗲𝘀𝘂𝗹𝘁𝘀: 𝗪𝗵𝘆 𝗜 𝗳𝗲𝗹 𝗲𝗺𝗯𝗮𝗿𝗿𝗮𝘀𝘀𝗲𝗱
I recently ran a security audit on all my side projects. This includes my FastAPI backend, Telegram bots, PWA, and Streamlit apps.
I thought my code was safe because I was careful. I was wrong.
I am sharing these real production bugs to help you avoid them. These are not theoretical checklists. These are mistakes I actually made.
The Conditional Authentication Trap I wrote code that checked if an API secret existed before verifying it. If the environment variable was missing, the check skipped entirely. This meant my entire API was open to the public. Rule: If a secret is missing, fail hard with a 500 error. Never skip authentication.
The Git History Leak I once hardcoded an API key for a quick test. I moved it to a .env file later and thought it was fixed. But Git remembers everything. Anyone can find that key in my commit history. Rule: If you commit a key, assume it is stolen. Rotate it immediately. Use git-filter-repo to clean your history.
The Debug Endpoint Leak I left a /debug/config endpoint in production to help me troubleshoot. It exposed my database URLs and environment settings. Rule: Remove all debug endpoints before deployment. Use logs instead.
Leaking System Info via Errors I used str(e) in my error responses. This sent database errors and file paths directly to the user. Attackers use this to map your infrastructure. Rule: Log the detailed error for yourself. Send a generic "Internal Server Error" to the client.
The XSS Risk in Frontend I used innerHTML to render user content. This allowed scripts to run in other users' browsers. Rule: Always escape HTML. Treat innerHTML as a way to execute arbitrary code.
Missing Rate Limits I had endpoints that called expensive AI models without any limits. A single loop or a stolen key could cost me hundreds of dollars. Rule: Authentication stops unauthorized users. Rate limiting stops authorized users from abusing your system.
Permissive CORS Policy I used allow_origins=["*"] in production. This allows any site to make requests to your API. Rule: Only allow your specific frontend domain.
임시 파일 누수 파일을 처리하는 동안 코드가 충돌하면, 임시 파일이 디스크에 영구적으로 남게 됩니다. 이는 공간을 낭비하고 민감한 데이터를 유출할 수 있습니다. 규칙: 오류가 발생하더라도 파일이 삭제되도록
try-finally블록을 사용하세요.
새로운 필수 체크리스트:
코딩 전:
• .gitignore 생성
• .env.example 생성
모든 엔드포인트에 대해: • 인증 추가 • 일반적인 에러 메시지 사용 • 비용이 많이 드는 작업에 속도 제한(rate limits) 추가
커밋 전: • diff에서 비밀 정보(secrets) 스캔
배포 전: • 의존성(dependencies)에 대한 보안 감사 실행
보안 문제는 우연히 발생하지 않습니다. "TODO" 주석과 프로덕션 환경에 영원히 남게 되는 "임시" 수정 사항들 때문에 발생합니다.
버그를 고치는 것은 지루한 일입니다. 보안 침해를 해결하는 것은 막대한 비용이 듭니다.