Debian comes with an outdated OpenSSL version which has security vulnerabilities.

apt-get install autoconf python libtool build-essential

wget ftp://ftp.openssl.org/source/openssl-1.0.2i.tar.gz
tar xfz openssl-1.0.2i.tar.gz

cd openssl-1.0.2i
./config --prefix=/usr zlib-dynamic --openssldir=/etc/ssl shared
make
make test
sudo make
sudo make install

openssl version