Php check if ssl certificate is valid

Is is possible to get the details like if a domain [say www.example.com] is HTTPS ready?

I need to validate some URLs, whether they have SSL certificate or not. I know, by using $_SERVER['HTTPS'] we can check our server details. but how can I achieve the same for other domains.

Any help would be much appreciated.

asked Dec 29, 2014 at 12:43

Krishna MohanKrishna Mohan

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6

Finally, I've ended up with the following my code:

$stream = stream_context_create [array["ssl" => array["capture_peer_cert" => true]]];
$read = fopen["//www.example.com", "rb", false, $stream];
$cont = stream_context_get_params[$read];
$var = [$cont["options"]["ssl"]["peer_certificate"]];
$result = [!is_null[$var]] ? true : false;

If HTTPS is enabled for a domain, var_dump[$var] gives the output as shown:

resource[4] of type [OpenSSL X.509] 

If it doesn't exist it returns NULL.

I've checked a few domains. It seems to be working fine. I hope it will help someone.

answered Dec 30, 2014 at 13:24

Krishna MohanKrishna Mohan

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1

This function will not only check if the domain has a SSL certificate, but also confirms, if the certificate matches the requested domain.

The most important part is the function openssl_x509_parse which parses the certificate and returns all the details as array.

function has_ssl[ $domain ] {
    $res = false;
    $stream = @stream_context_create[ array[ 'ssl' => array[ 'capture_peer_cert' => true ] ] ];
    $socket = @stream_socket_client[ 'ssl://' . $domain . ':443', $errno, $errstr, 30, STREAM_CLIENT_CONNECT, $stream ];

    // If we got a ssl certificate we check here, if the certificate domain
    // matches the website domain.
    if [ $socket ] {
        $cont = stream_context_get_params[ $socket ];
        $cert_ressource = $cont['options']['ssl']['peer_certificate'];
        $cert = openssl_x509_parse[ $cert_ressource ];

        // Expected name has format "/CN=*.yourdomain.com"
        $namepart = explode[ '=', $cert['name'] ];

        // We want to correctly confirm the certificate even 
        // for subdomains like "www.yourdomain.com"
        if [ count[ $namepart ] == 2 ] {
            $cert_domain = trim[ $namepart[1], '*. ' ];
            $check_domain = substr[ $domain, -strlen[ $cert_domain ] ];
            $res = [$cert_domain == $check_domain];
        }
    }

    return $res;
}

answered Dec 30, 2016 at 15:22

PhilippPhilipp

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4

Here is a different solution that I found somewhere on github [cannot find the repo again...]

It's a similar approach to the accepted answer, but uses fsockopen to test, if we can establish a SSL connection on port 443. If the connection is refused then the domain does not have a ssl certificate.

function has_ssl[ $domain ] {
    $ssl_check = @fsockopen[ 'ssl://' . $domain, 443, $errno, $errstr, 30 ];
    $res = !! $ssl_check;
    if [ $ssl_check ] { fclose[ $ssl_check ]; }
    return $res;
}

// Test it:
print_r[ has_ssl['google.com'] ];

answered Dec 30, 2016 at 13:40

PhilippPhilipp

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2

There's no way to check if the certificate is secure or not using PHP alone without API [green padlock]

But you can use this, which use a API: //github.com/spatie/ssl-certificate

cs95

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answered Aug 5, 2019 at 22:49

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