Download SSL Corproate Proxy Cert via Linux CLI - linux

How do I download a proxy's SSL cert and save it to a file using the Linux command line.
It's possible to download an ssl cert via the openssl tool: https://superuser.com/questions/97201/how-to-save-a-remote-server-ssl-certificate-locally-as-a-file. But this does not work when behind a corporate proxy that re-writes the SSL cert. I would like to download the proxy's ssl cert. Changing the HOST and PORT to my proxy's host and port does not work either.
Downloading the cert using my browser works but I need to do this in a bash script.

You can only extract certificates from the connection which actually get send inside the connection. Within a MITM proxy the root CA you want to have usually does not get send since it is expected to be installed locally as trusted, similar to a public root CA. And the reason you can extract this MITM CA within your browser is because the browser already has this CA as trusted in the CA store and can thus export it.

As mentioned here, openssl 1.1.0 and above support the -proxy argument so you can get the proxy's certificates with a command like (jcenter.bintray.com is just an example host to connect to)
openssl s_client -showcerts -proxy $https_proxy -connect jcenter.bintray.com:443
Also see this script for a more complete example how to import the certificate(s) to a JVM keystore and the system certificates.

Related

Simulate MQTT TLS login by MQTT.FX in linux?

I am having some problems using mosquitto client in linux, more specifically I need to use mosquitto_sub but I don't really get how I should authenticate.
All I have is a json config file for MQTT.Fx, that works fine when imported in that application. I can see there are username and password, as well as host information, and that SSL/TSL is enabled.
My question is: how can I do the same thing that MQTT.Fx does automatically since option CA signed server certificate is selected? I have been trying a lot of alternatives, like downloading server certificate and passing it as --cafile, generating new certificate, signing them, editing mosquitto.conf, but I didn't match the right combination of operations.
Any suggestion, please?
Edit: here is current command:
mosquitto_sub -h myhost.example -p 8883 -i example1 -u myusername -P mypassword -t XXXXXXXXXXXX/# --cafile /etc/mosquitto/trycert.crt
where file trycert.crt contains the response to following request (of course only part between BEGIN CERTIFICATE and END CERTIFICATE)
openssl s_client -showcerts -servername myhost.example -connect myhost.example:8883 </dev/null
All the times I had problems with MQTT over SSL its been that the server cert chain of trust broken on my client. In other words, the server i am connecting to has a cert. This cert is authorized by another cert and so forth. Each of the certs in the chain need to be on the client.
If any of these certs are missing, the chain of trust is broken and the stack will abort the connection.

How to disable all built-in SSL certificates in wget and just use self-signed one?

I would like to use wget (or curl) to connect to my website using only my self signed SSL certificate. The website also has some root CA signed wildcard certificates.
wget -O- --ca-certificate=my.pem --ca-directory=/dev/null --certificate=my.pem https://example.com
This works on my server with the self signed certificate, but it also establishes a connection to any regular SSL-enabled public website (when changing example.com). So it seems to not disable build-in root CAs.
How can I disable all build-in root CAs in wget so only my private certificate can establish a secure connection and it fails without (to test if the self signed cert is installed correctly)?
Got some help on stackexchange: real openssl s_client (check with openssl version) supports the parameter -verify_return_error which will catch certificate verification errors.

SSL: Servers certificate chain is incomplete

I bought a PositiveSSL Wildcard from https://www.ssls.com/
I have received 3 files a .ca-bundle a .crt and a .p7b.
I configured the certificates with NGINX but I'm getting an error:
"Servers certificate chain is incomplete"
https://www.ssllabs.com/ssltest/analyze.html?d=api.billgun.com
How can I fix this?
Servers certificate chain is incomplete
means you don't have intermediate certificates, certificates have expired or are in wrong order.
It looks like you don't have any intermediate certificates: https://www.sslshopper.com/ssl-checker.html#hostname=https://api.billgun.com/.
When you open your site in a browser you will get green padlock because browsers can download missing intermediate certificates but other tools won't be able to connect ie. curl:
curl -I 'https://api.billgun.com/'
curl: (60) server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
More details here: http://curl.haxx.se/docs/sslcerts.html
or openssl:
openssl s_client -connect api.billgun.com:443
CONNECTED(00000003)
depth=0 OU = Domain Control Validated, OU = PositiveSSL Wildcard, CN = *.billgun.com
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=0 OU = Domain Control Validated, OU = PositiveSSL Wildcard, CN = *.billgun.com
verify error:num=21:unable to verify the first certificate
verify return:1
---
Certificate chain
0 s:/OU=Domain Control Validated/OU=PositiveSSL Wildcard/CN=*.billgun.com
i:/C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO RSA Domain Validation Secure Server CA
---
The fastest way to generate correct chain is to:
open your site in a browser
click on green padlock and display certificate properties
export every certificate in the chain (in your case, you should get 3 files: -billguncom.crt, COMODORSADomainValidationSecureServerCA.crt, COMODORSACertificationAuthority.crt)
combine the files in order from leaf to root cert:
cat -- -billguncom.crt COMODORSADomainValidationSecureServerCA.crt COMODORSACertificationAuthority.crt > billgun_com.crt
install new cert on server
test nginx cofiguration nginx -t
restart server service nginx restart
There is a tool to automate the procedure of producing a bundle of correctly chained certificates. https://github.com/zakjan/cert-chain-resolver (I'm the author.)
Usage:
cert-chain-resolver -o domain.bundle.pem domain.pem
domain.pem is your input certificate
domain.bundle.pem is the certificate bundle, that you can use in your web server configuration

SSL handshake failure with node.js https

I have an API running with express using https. For testing, I've been using tinycert.org for the certificates, which work fine on my machine.
I'm using docker to package up the app, and docker-machine with docker-compose to run it on a digital ocean server.
When I try to connect with Chrome, I get ERR_SSL_VERSION_OR_CIPHER_MISMATCH. When running this with curl, I get a handshake failure: curl: (35) SSL peer handshake failed, the server most likely requires a client certificate to connect.
I tried to debug with Wireshark's SSL dissector, but it hasn't given me much more info: I can see the "Client Hello" and then the next frame is "Handshake Failure (40)".
I considered that maybe node on the docker container has no available ciphers, but it has a huge list, so it can't be that. I'm unsure as to what's going on and how to remedy it.
EDIT
Here's my createServer() block:
let app = express();
let httpsOpts = {
key: fs.readFileSync("./secure/key.pem"),
cert: fs.readFileSync("./secure/cert.pem")
};
let port = 8080;
https.createServer(httpsOpts, app).listen(port);
I've had this problem for a really long time too, there's a weird fix:
Don't convert your certs to .pem; it works fine as .crt and .key files.
Add ca: fs.readFileSync("path to CA bundle file") to the https options.
It looks like your server is only sending the top certificate and the CA bundle file has the intermediate and root certificates which you'll need for non-browser use.
IMPORTANT! Reinstall or update node to the latest version.
You can use sudo apt-get upgrade if you're on Linux (it may take a while).
Re-download your certificate or get a new one.
If you are acting as your own certificate authority it could be not recognizing / trusting the certificate, so try testing your site on ssllabs.com.
If you're using the http2 API try adding allowHTTP1: true to the options.

IIS Client certificate not working. Returns 403 error

I'm trying to setup IIS 8 (Windows Server 2012) to accept client certificates for a secured WebAPI endpoint. Following this post I created a self signed certificate and a client certificate:
makecert.exe -r -n "CN=MyCompany" -pe -sv MyCompany.pvk -a sha1 -len 2048 -cy authority MyCompany.cer
makecert.exe -iv MyCompany.pvk -ic MyCompany.cer -n "CN=MY Client" -pe -sv MyClient.pvk -a sha1 -len 2048 -sky exchange MyClient.cer -eku 1.3.6.1.5.5.7.3.2
pvk2pfx.exe -pvk MyClient.pvk -spc MyClient.cer -pfx MyClient.pfx -po THE_PASSWORD
I installed the root certificate MyCompany.cer on the IIS server, then on IIS Manager/SSL Settings I selected the "Accept" radio button to allow the website accept client certificates.
On the client side a have a C# test console app that loads the client cert MyClient.pfx file and calls the WebAPI endpoint:
var certHandler = new WebRequestHandler();
certHandler.ClientCertificateOptions = ClientCertificateOption.Manual;
certHandler.UseProxy = false;
var certificate = new X509Certificate2(File.ReadAllBytes(#"C:\MyClient.pfx"), "THE_PASSWORD");
certHandler.ClientCertificates.Add(certificate);
var client = new HttpClient(certHandler);
var result = client.GetAsync("https://MyServer/api/MyEndpoint").Result;
string resultStr = result.Content.ReadAsStringAsync().Result;
Console.WriteLine(resultStr);
I'm getting back a 403 error:
403 - Forbidden: Access is denied.
You do not have permission to view this directory or page using the credentials that you supplied.
I tried the same setup on my local IIS (Windows 7): Imported the MyCompany.cer file, setup SSL in IIS. This time everything works fine and the WebAPI endpoint can see the client certificate with no problem.
Any ideas?
-- Update 1
I enabled Failed REquest Tracing on IIS and I get this:
<failedRequest url="https://myserver:443/"
siteId="35"
appPoolId="CertTest"
processId="7248"
verb="GET"
authenticationType="NOT_AVAILABLE" activityId="{00000000-0000-0000-B0AA-0280000000E0}"
failureReason="STATUS_CODE"
statusCode="403.16"
triggerStatusCode="403.16"
timeTaken="0"
xmlns:freb="http://schemas.microsoft.com/win/2006/06/iis/freb"
>
If I understand right the error is 403.16. I understand that happens when the certificate on the server is not imported into the Trusted Root Certification Authorities under Local Computer. I double checked and that's not my case.
Check that
On your IIS machine you have installed Server's cert issuer certificate to Trusted Root Certification Authorities under Local Computer
On your IIS machine you have installed Client's cert issuer certificate to Trusted Root Certification Authorities under Local Computer
On your client machine you have installed Server's cert issuer certificate to Trusted Root Certification Authorities under Windows User that runs console app
On your client machine you have installed Client's cert issuer certificate to Trusted Root Certification Authorities under Windows User that runs console app. Or you can make sure to include all necessary certificate's chain to pfx file
In code use X509Certificate2's ctor version with X509KeyStorageFlags.UserKeySet explicitly.
If it won't help,
try to open url in IE (under the same Windows User Account that runs console app).
open *.cer files with double click on a client machine under Windows User Account that runs console app and see what Windows says about they validity.
change IIS SSL settings to ignore client certificate to see if it's all good with server certificate. Try both browser and console app.
Have a look at the following blog post: https://configmgrblog.com/2014/02/23/configmgr-2012-r2-internet-facing-mp-windows-server-2012-r2-note/
In short: There seems to be an issue with client certificate authentication and IIS 8.x in Windows Server 2012 (R2), that might cause status code 403.16 to be returned when using client certificates. Solution:
Set registry DWORD entries under HKey_Local_Machine\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL on your server:
SendTrustedIssuerList = 0
ClientAuthTrustMode = 2
The post further mentions that if your get a 403.13 (client certificate revoked) after fixing the in initial problem (403.16), you should disable client certificate revocation check on the server. I would not recommend that. Please make sure that the CDP is correctly set in the client certificate. The CDP has to be reachable from the server and the revocation list should be valid and not outdated.

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