Check for TLS cert expiration

check_tls.sh

#!/bin/bash
SECONDS=0
RED='\033[0;31m'
WHITE='\033[1;37m'
CYAN='\033[0;36m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

list=''

days='7'

echo ""
echo -e "${CYAN}Checking domain TLS cert expiration dates...\n${NC}"
echo ""

for domain in $list; do
	  echo -e "Checking domain: ${WHITE}${domain}${NC}"
	  out=$(echo | openssl s_client -showcerts -servername ${domain} -connect ${domain}:443 2>/dev/null | openssl x509 -inform pem -noout -text | grep 'Not After' | awk '{ print $4, $5, $7 }')
	  echo -e "Expires:         ${YELLOW}${out}${NC}" 
    EXPDUR=$(($(date +%s) + (86400*7)))
    EXPDAT=$(date -d "${out}" +"%s")
    HUMDATE=$(date -d @${EXPDAT})
        if [ ${EXPDUR} -gt ${EXPDAT} ] ; then
            echo -e "\n${RED}*** WARNING TLS cert expires in less than 7 days.\n*** The TLS cert for ${domain} will expire on ${HUMDAT}${NC}\n"
        fi
    openssl s_client -showcerts -connect ${domain}:443 </dev/null 2>/dev/null|openssl x509 -outform PEM > ${domain}.pem
    file=${domain}.pem
    openssl x509 -checkend $(( 86400 * $days )) -in ${file} > /dev/null
    if [ $? != 0 ]; then
        echo -e "${RED}==> Certificate ${domain} will expire in less than ${days} days... Please renew soon.${NC}"
        openssl x509 -enddate -in ${domain} -noout
#        else 
#      echo -e "${WHITE}${domain} is not expiring in less than ${days} days. All good.${NC}"
    fi
    rm ${domain}.pem            
    echo -e "===========================================================================\n"
done

displaytime () {
   local T=$SECONDS
   local D=$((T/60/60/24))
   local H=$((T/60/60%24))
   local M=$((T/60%60))
   local S=$((T%60))
   [[ $D > 0 ]] && printf '%d days ' $D
   [[ $H > 0 ]] && printf '%d hours ' $H
   [[ $M > 0 ]] && printf '%d minutes ' $M
   [[ $D > 0 || $H > 0 || $M > 0 ]] && printf 'and '
   printf '%d seconds\n' $S
}

echo ""
echo "Took $(displaytime) to complete ${0}."
exit 0

# To do
# Add email alert if expiring
# improve script so cert saving to file system is not needed

Requires ssmtp package to be installed on system
sudo apt install ssmtp

/etc/ssmtp/ssmtp.conf

root=username@gmail.com
mailhub=smtp.gmail.com:465
FromLineOverride=YES
AuthUser=username@gmail.com
AuthPass=super_secret_password
UseTLS=YES

echo "Testing...1...2...3" | ssmtp -F "Sender full name" -f "from full name" username@gmail.com

{
    echo To: my_email@domain.com
    echo From: from_email@example.com
    echo Subject: mov files greater than 1M
    echo
    find /path/to/folder/ -type f -size +1M -name "*.mov"
} | ssmtp my_email@domain.com