Scripting OpenSSL just to extract Certificate Chain and Cert Expiry date
2 min readJan 20, 2021
usecase
- The concern is documenting the need to quickly check the
- certificate chain
- certificate expiry date
- using a single command from PowerShell with OpenSSL
1. steps
function test-certificate($domain) {
$domain += ":443"
openssl s_client -connect $domain | sls "certificate chain" -Context 5
openssl- and
openssl s_client -connect github.com:443 | openssl x509 -noout -enddate2. passing the “Q” key into the command
s_clientopens the client that is awaiting for the input- I need to pass the
qinto the script for thes_clientto end gracefully and immediatelly - which is achieved with
write-output "q" | ... echois alias forwrite-outputcmdlet
echo "q" | openssl s_client -connect github:4433. solution
- just adding the following to the
$profile - passing the domain e.g.
cert github.comand pressingQto continue - this is just for a quick interactive check
#$profile
function test-certificate($domain, $contextLength = 10) {
$domain += ":443"
echo "q" | openssl s_client -connect $domain | openssl x509 -noout -enddate | sls "notAfter.*"
echo "q" | openssl s_client -connect $domain | sls "certificate chain" -Context $contextLength
write-host "~~~" -ForegroundColor darkcyan
write-host "If needed, pass a desired output length after domainname" -ForegroundColor darkcyan
}
Set-Alias cert test-certificate