I am working with an external company. Lets call them evilcorp.com. I want to use openssl to debug a two way SSL handshake.
https://evilcorp.com is setup to not require client authentication.
https://evilcorp.com/webservices is setup to require client authentication.
How can I specify this path in openssl. So basically this works:
openssl s_client -connect evilcorp.com:443
But this does not work and gives me gethostbyname failure
openssl s_client -connect evilcorp.com/webservices:443
How can I get this to work (if possible)
You have a very simple error in the address. Here's the fix:
"openssl s_client -connect evilcorp.com:443/webservice"
You had the 443 at the end - it needs to go directly after to the domain name.
I'm not sure if this can be done at all but if it can be done then you first have to use openssl to connect to the clients host and already specify the client certificates. Then inside the successful connection you need to speak HTTP to access the relevant page.
I.e. you first connect:
$ openssl s_client -connect host:port -cert cert.pem -key key.pem
... CONNECTED
... Verify return code...
---
And then access the URL using the HTTP protocol
GET /protected_page/ HTTP/1.0
Host: example.org
<empty line>
Note that the last line must be an empty line according to the HTTP protocol. It might also that you need to use the -crlf option in openssl to get the line ends correct in case you have a strict web server. If all goes right the server should now issue a renegotiation request to the client, i.e another TLS handshake is done.
Related
I can use the openssl s_server command to accept TLS sessions from clients, and to require mutual TLS - i.e. request client certificate - using a command such as: -
openssl s_server -accept 4433 -cert myCert.crt -key -myKey.pem -Verify 2 -CAfile myCA.crt
When I connect from a client, I can see from tracing that s_client sends a certificate request, correctly stipulating the certificate contained within myCA.crt. However it seems that s_server will accept any client certificate, regardless of whether it was signed by myCA.crt or not - i.e. it doesn't care which client cert is sent.
Does anyone know if this is expected behaviour, or am I doing something wrong?
openssl s_server and s_client by default verify the peers certificate and show the verification status but don't stop on errors. If this is necessary use the -verify_return_error option.
The classic was of dumping a certificate with openssl s_client -showcerts -connect HOST:443 does not work if you want to debug a https_proxy based connection.
Assuming that https_proxy=http://192.168.1.1:3128 how can I dump the certificate returned by the proxy when making a http request to, lets say https://pypi.org
Clearly the returned certificate is supposed to created on the fly by the proxy using its own CA authority.
I want to dump this certificate because while curl accepts it as valid without any problems I found that python-requests chokes.
I am not able to verify webmaster account of one of my client.
Google is saying "Verification failed - The connection to your server timed out."
When I tried to do wget the URL, I found below error. Can someone please help me resolving this?
[pdurgapal]$ wget https://atlanticdiscountstore.com
--2017-06-28 11:48:48-- https://atlanticdiscountstore.com
Resolving atlanticdiscountstore.com... 188.241.58.18
Connecting to atlanticdiscountstore.com|188.241.58.18|:443... connected.
ERROR: cannot verify atlanticdiscountstore.com’s certificate, issued by “/CN=baldwincountyunited.com”:
Self-signed certificate encountered.
ERROR: certificate common name “baldwincountyunited.com” doesn’t match requested host name “atlanticdiscountstore.com”.
To connect to atlanticdiscountstore.com insecurely, use ‘--no-check-certificate’.
[pdurgapal]$
You must be using a very old version of wget which has no support for SNI. When using a proper client with support for SNI the certificate can be verified. Apart from that the server is terrible slow in responding after the TLS handshake is successfully done, but this is not the issue you asked about.
To demonstrate the problem an access to the site without SNI:
$ openssl s_client -connect atlanticdiscountstore.com:443 |\
openssl x509 -text
...
Subject: CN=baldwincountyunited.com
...
X509v3 Subject Alternative Name:
DNS:baldwincountyunited.com, DNS:mail.baldwincountyunited.com, DNS:www.baldwincountyunited.com
and with SNI:
$ openssl s_client -connect atlanticdiscountstore.com:443 \
-servername atlanticdiscountstore.com |\
openssl x509 -text
...
Subject: ... CN=*.atlanticdiscountstore.com
...
X509v3 Subject Alternative Name:
DNS:*.atlanticdiscountstore.com, DNS:atlanticdiscountstore.com
I am developing a client/server application with TLS. My idea is to use a certificate on the client so it is authenticated by the server. Also another certificate on the server so the client is also able to authenticate that it is connecting to the right server.
I want first to test and use openssl s_server and openssl s_client to validate the proposal.
Until now I have created a CA private key on the server, I have created a root certificate. With the root certificate I have signed two CSR, so I get one certificate for the server and one certificate for the client.
I also have installed the client certificate + root certificate on the client, and the server certificate + root certificate on the server.
I want now to try to establish a connection between openssl s_server and openssl s_client and verify that they get both authenticated mutually, but I cannot wrap my mind with the documentation on how to do it. Any help or any guide on that?
Once I have that set up, the next step is to test the own developed client against that server, and our own developed server against the s_client. Can we use that for testing?
Thanks
It looks like you are trying to set up a root of trust with (1) s_client and s_server for testing; and (2) programmatically within your code using OpenSSL.
To ensure openssl s_client (or openssl s_server) uses your root, use the following options:
-CAfile option to specify the root
-cert option for the certificate to use
-key option for the private key of the certificate
See the docs on s_client(1) and s_server(1) for details.
To do the same programmatically on the client, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate to specify the client certificate
SSL_CTX_use_PrivateKey to load the private key for the client certificate
To do the same programmatically on the server, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate_chain_file to specify the server certificate
SSL_CTX_use_PrivateKey to load the private key for the server certificate
SSL_CTX_set_client_CA_list to tell the client to send its client certificate
If you don't want to use the parameters for every connection (i.e. the common context), then set it for each SSL connection with, for example, SSL_use_certificate and SSL_use_PrivateKey.
A lot goes on with SSL_CTX_set_client_CA_list. It (1) loads the CA's to the server uses to verify a client, (2) it causes the server to send a list of CAs it accepts when verifing a client, and (3) it triggers the ClientCertificate message at the client if the client has a certificate that satisfies the server's accepted CAs list.
Also see the docs on SSL_CTX_load_verify_locations(3), SSL_CTX_use_certificate(3), SSL_CTX_set_client_CA_list and friends.
The easiest certificate and key format to use is PEM. PEM is the one that uses, for example, ----- BEGIN CERTIFICATE -----. For the server certificate, be sure the file is a concatenation of the server's certificate and any intermediates needed by the client to build the chain.
Having the server send all required certificates is standard practice for a problem known as the "which directory" problem. Its a well known problem in PKI, and its essentially the problem that clients don't know where to go to fetch missing intermediate certificates.
In general, you now know the functions that you need to use. Download a small server like nginx, and see how a production server uses them in practice. You could even use a SQL server like Postgres since it sets up a SSL/TLS server. Simply search the source files for SSL_CTX_load_verify_locations or SSL_load_verify_locations, and you will find the right place.
Though I don't recommend it, you could even look at s_client.c and s_server.c. They are located in <openssl dir>/apps. But the code can be difficult to read at times.
Generate two pairs of certificates/keys, one for the server and one for the client. Also create test.txt with any content.
To set up an SSL server that checks a client certificate, run the following command:
openssl s_server -cert server_cert.pem -key server_key.pem -WWW -port 12345 -CAfile client_cert.pem -verify_return_error -Verify 1
To test the server with client certificate, run the following command:
echo -e 'GET /test.txt HTTP/1.1\r\n\r\n' | openssl s_client -cert client_cert.pem -key client_key.pem -CAfile server_cert.pem -connect localhost:12345 -quiet
Alternatively you can use curl command:
curl -k --cert client_cert.pem --key client_key.pem https://localhost:12345/test.txt
I am developing a client/server application with TLS. My idea is to use a certificate on the client so it is authenticated by the server. Also another certificate on the server so the client is also able to authenticate that it is connecting to the right server.
I want first to test and use openssl s_server and openssl s_client to validate the proposal.
Until now I have created a CA private key on the server, I have created a root certificate. With the root certificate I have signed two CSR, so I get one certificate for the server and one certificate for the client.
I also have installed the client certificate + root certificate on the client, and the server certificate + root certificate on the server.
I want now to try to establish a connection between openssl s_server and openssl s_client and verify that they get both authenticated mutually, but I cannot wrap my mind with the documentation on how to do it. Any help or any guide on that?
Once I have that set up, the next step is to test the own developed client against that server, and our own developed server against the s_client. Can we use that for testing?
Thanks
It looks like you are trying to set up a root of trust with (1) s_client and s_server for testing; and (2) programmatically within your code using OpenSSL.
To ensure openssl s_client (or openssl s_server) uses your root, use the following options:
-CAfile option to specify the root
-cert option for the certificate to use
-key option for the private key of the certificate
See the docs on s_client(1) and s_server(1) for details.
To do the same programmatically on the client, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate to specify the client certificate
SSL_CTX_use_PrivateKey to load the private key for the client certificate
To do the same programmatically on the server, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate_chain_file to specify the server certificate
SSL_CTX_use_PrivateKey to load the private key for the server certificate
SSL_CTX_set_client_CA_list to tell the client to send its client certificate
If you don't want to use the parameters for every connection (i.e. the common context), then set it for each SSL connection with, for example, SSL_use_certificate and SSL_use_PrivateKey.
A lot goes on with SSL_CTX_set_client_CA_list. It (1) loads the CA's to the server uses to verify a client, (2) it causes the server to send a list of CAs it accepts when verifing a client, and (3) it triggers the ClientCertificate message at the client if the client has a certificate that satisfies the server's accepted CAs list.
Also see the docs on SSL_CTX_load_verify_locations(3), SSL_CTX_use_certificate(3), SSL_CTX_set_client_CA_list and friends.
The easiest certificate and key format to use is PEM. PEM is the one that uses, for example, ----- BEGIN CERTIFICATE -----. For the server certificate, be sure the file is a concatenation of the server's certificate and any intermediates needed by the client to build the chain.
Having the server send all required certificates is standard practice for a problem known as the "which directory" problem. Its a well known problem in PKI, and its essentially the problem that clients don't know where to go to fetch missing intermediate certificates.
In general, you now know the functions that you need to use. Download a small server like nginx, and see how a production server uses them in practice. You could even use a SQL server like Postgres since it sets up a SSL/TLS server. Simply search the source files for SSL_CTX_load_verify_locations or SSL_load_verify_locations, and you will find the right place.
Though I don't recommend it, you could even look at s_client.c and s_server.c. They are located in <openssl dir>/apps. But the code can be difficult to read at times.
Generate two pairs of certificates/keys, one for the server and one for the client. Also create test.txt with any content.
To set up an SSL server that checks a client certificate, run the following command:
openssl s_server -cert server_cert.pem -key server_key.pem -WWW -port 12345 -CAfile client_cert.pem -verify_return_error -Verify 1
To test the server with client certificate, run the following command:
echo -e 'GET /test.txt HTTP/1.1\r\n\r\n' | openssl s_client -cert client_cert.pem -key client_key.pem -CAfile server_cert.pem -connect localhost:12345 -quiet
Alternatively you can use curl command:
curl -k --cert client_cert.pem --key client_key.pem https://localhost:12345/test.txt