How to hack any Whatsapp account

 Identifying weak implementations of

SSL/TLS

As you learned in the previous section, TLS is a combination of various encryption

algorithms packaged into one in order to provide confidentiality, integrity, and

authentication. In the first step, when two endpoints negotiate for an SSL connection, they

identify the common cipher suites supported by them. This allows SSL to support a wide

variety of devices, which may not have the hardware and software to support the newer

ciphers. Supporting older encryption algorithms has a major drawback. Most older cipher

suites are easily breakable in a reasonable amount of time by cryptanalysts using the

computing power available today.

The OpenSSL command-line tool

In order to identify the cipher suites negotiated by the remote web server, you can use the

OpenSSL command-line tool that comes preinstalled on all major Linux distributions, and it

is also included in Kali Linux. The tool can be used to test the various functions of the

OpenSSL library directly from the bash shell without writing any code. It is also used as a

troubleshooting tool

The following example uses the s_client command-line option that establishes a

connection to the remote server using SSL/TLS. The output of the command is difficult to

interpret for a newbie, but it is useful for identifying the TLS/SSL version and cipher suites

agreed upon between the server and the client:

The OpenSSL utility contains various command-line options that can be used to test the

server using specific SSL versions and cipher suites. In the following example, we are trying

to connect using TLS version 1.2 and a weak algorithm, RC4:

openssl s_client -tls1_2 -cipher 'ECDHE-RSA-AES256-SHA' -connect

<target>:<port>

 You will often see cipher suites written as ECDHE-RSA-RC4-MD5. The format is broken

down into the following parts:

ECDHE: This is a key exchange algorithm

RSA: This is an authentication algorithm

RC4: This is an encryption algorithm

MD5: This is a hashing algorithm

A comprehensive list of SSL and TLS cipher suites can be found

at https://www.openssl.org/docs/apps/ciphers.html.

SSLScan

Although the OpenSSL command-line tool provides many options to test the SSL

configuration, the output of the tool is not user friendly. The tool also requires a fair amount

of knowledge about the cipher suites that you want to test.

Kali Linux comes with many tools that automate the task of identifying SSL

misconfigurations, outdated protocol versions, and weak cipher suites and hashing

algorithms. One of the tools is SSLScan, which can be accessed by going to Applications |

Information Gathering | SSL Analysis.

By default, SSLScan checks if the server is vulnerable to the CRIME and Heartbleed

vulnerabilities. The -tls option will force SSLScan only to test the cipher suites using the

TLS protocol. The output is distributed in various colors, with green indicating that the

cipher suite is secure and the sections that are colored in red and yellow are trying to attract

your attention:

The cipher suites supported by the client can be identified by running the following

command. It will display a long list of ciphers that are supported by the client:

sslscan -show-ciphers www.example.com:443

If you want to analyze the certificate-related data, use the following command that will

display detailed information on the certificate:

sslscan --show-certificate --no-ciphersuites www.amazon.com:443

The output of the command can be exported in an XML document using the -

xml=<filename> option.