About shell shock vulnerability and poodle attack. how to fix these vulnerabilities

1. Shell shock & Poodle
Vulnerabilities, Fix
-Sasidhar Gogulapati

2. Shellshock is a security bug in Bash command-line
interpreter(CLI)
Revealed by Linux expert Stephane Chazelas on 24th
September, 2014. It’s a 10 years old bug !!
Allows attackers to gain unauthorized access to systems
by executing arbitrary commands
High impact on Linux and Mac OS, where Bash is the
default CLI
Shell Shock Vulnerability

3.  Found under Bash’s parsing code which unintentionally executes
commands when concatenated, to the end of function definitions that are
stored in the values of environment variables.
Where the bug occurs ?

4. HTTP Servers: Servers that run on CGI have the
capability to expose Bash to a HTTP request,
hence a malicious HTTP request can inject
arbitrary commands onto the server with Bash
invoking it to execute them
SSH: Bash is capable of overcoming the
restriction of user authentication with privileged
escalations for accessing the commands
How attacker exploiting it ?

5. Execute the following commands from terminal:
If the output contains the word ‘vulnerable’, then
system is vulnerable
How to test it?

6. By upgrading to the latest version of Bash
“yum update bash” is the command for CentOS
and Red Hat Linux
How to fix it ?

7. “Padding Oracle On Downgraded Legacy
Encryption”
Man-in-the-middle exploit which takes advantage
of security software client’s fallback to SSL 3.0
Google security team discovered this on October
14, 2014
If attackers successful exploit, they need only 256
SSL 3.0 requests to reveal one byte of encrypted
message
Poodle Attack

8. Poodle can be used to target browser based
communication that relies on SSL 3.0 (Secure
Sockets Layer) for encryption and authentication
This allows attacker to paddle data at the end of
block cipher, so that the encryption cipher
became less secured
Poodle can force the browser to use SSL 3.0
Where the bug occurs ?

9. Disable SSL 3.0 on all protocols
Enable TLS(Transport Layer Security) 1.0
Prevent TLS 1.0 downgrade attacks by ensuring
both client and server supports only TLS
How to fix it?

10. Thank You