Build openssl (with SSLv2/3 support for security testing)

build-openssl.sh

#!/bin/bash

# Cache sudo password
sudo -v

# Get latest OpenSSL 1.0.2 version from https://openssl.org/source/
# v1.1.0 seems to have removed SSLv2/3 support
openssl_version=1.0.2k

# Install build dependencies
sudo apt -y install build-essential

# Build OpenSSL
wget https://openssl.org/source/openssl-$openssl_version.tar.gz
tar -xvf openssl-$openssl_version.tar.gz
cd openssl-$openssl_version
# --prefix will make sure that make install copies the files locally instead of system-wide
# --openssldir will make sure that the binary will look in the regular system location for openssl.cnf
# no-shared builds a mostly static binary
./config --prefix=`pwd`/local --openssldir=/usr/lib/ssl enable-ssl2 enable-ssl3 no-shared
make depend
make
# -i continues on errors, since make install may try to put some files in /usr/lib/ssl, which we don't want
make -i install

# Install just the binary so we can use s_client -ssl2
mkdir -p ~/bin
sudo cp local/bin/openssl ~/bin/

# Cleanup
cd ..
rm -rf openssl-$openssl_version
rm openssl-$openssl_version.tar.gz

# (Optional) start a new login shell (to add ~/bin to the path, if necessary)
bash -l

# To test:
# $ openssl s_client -connect google.com:443 -ssl2 >/dev/null
# 139675635414688:error:1407F0E5:SSL routines:ssl2_write:ssl handshake failure:s2_pkt.c:412:
# $ openssl s_client -connect google.com:443 -ssl3 >/dev/null
# 140647504119456:error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number:s3_pkt.c:365: