HTTP channels in MEC (part 5)

Continuing the guide on how to setup HTTP channels in Infor M3 Enterprise Collaborator (MEC), I will illustrate how to setup the HTTPSOut channel for MEC to make requests using HTTP Secure (HTTPS), i.e. HTTP over SSL/TLS; I will investigate the channel’s features and drawbacks, and I will verify if it is safe to use (it is not).

Why it matters

It is important to use SSL/TLS in partner agreements that need to transfer via HTTP sensitive information such as names, addresses, bank account numbers, purchase orders, credit card numbers, financial transactions, health records, user names, passwords, etc. More generally, it is important to accelerate the adoption of cryptography.

HTTPS in brief

SSL/TLS is a security protocol that provides privacy for a client and a server to communicate over insecure networks. It is a communication layer that sits between a transport layer (usually TCP) and an application layer (for example HTTP). Secure Sockets Layer (SSL) is the original protocol and is not considered secure anymore. Transport Layer Security (TLS) is the successor and everybody should upgrade to its latest version 1.2. https is the scheme token in the URI that indicates we are using a dedicated secure channel often on port 443.

Properties

SSL/TLS provides the following properties of secure communication:

• Confidentiality, using a cipher to encrypt the plain text and prevent eavesdropping
• Integrity, using signed hashes to detect tampering
• Authentication, using digital certificates to affirm the identity of the entities

It can also provide non-repudiation, using digital signatures to assert the sender cannot deny having sent the message, provided the sender’s private key is not compromised or changed.

And depending on the key agreement protocol, it can also provide perfect forward secrecy, using ephemeral key exchanges for each session, to ensure that a message cannot be compromised if another message is compromised in the future.

Handshake

During the SSL/TLS handshake, the client and server exchange digital certificates and establish cipher suite settings. The connection bootstraps with asymmetric cryptography using public and private keys (which eliminates the problems of distributing shared keys), and then switches to symmetric cryptography using a temporary shared key for the session (which is several orders of magnitude faster).

Digital certificates

A digital certificate is a public key and the owner’s identity that have been verified and digitally signed by a certificate authority (CA). Public key infrastructure (PKI) is used to create, distribute, and revoke certificates. If an entity trusts a CA, then by transitive relation it will trust that any certificate the CA issues authenticates the owner of the certificate. There can be any number of intermediate CAs in the chain of certificates, and root CAs use self-signed certificates.

The client must verify the server certificate, and optionally the server may verify the client certificate:

• Verify the chain of trust
• Verify the hostname in the certificate using SubjectAltNames and Common Name; this could get tricky with wildcard patterns, null characters, and international character sets
• Verify the certificate’s activation and expiration dates
• Verify the certificate’s revocation status using a certification revocation list (CRL) or OCSP
• Check the X.509 certificate extensions (e.g. can this key sign new certificates?)
• Check that the certificates of the intermediate CAs have the CA bit set in the “Basic Constraints” field

Despite all that, validating certificates is difficult, and the CA model is broken.

Test

You can test HTTP over SSL/TLS and see the chain of certificates,

with cURL:

curl http://curl.haxx.se/ca/cacert.pem > cacert.pem
curl --verbose --cacert cacert.pem https://www.example.com/

with OpenSSL:

openssl s_client -connect www.example.com:443 -showcerts
GET / HTTP/1.1
Host: www.example.com:443

Proxy

A web proxy is a program that makes requests on behalf of a client. There are different types of web proxies, for example tunneling proxies, forward proxies, and reverse proxies. And there are different implementations, for example, explicit proxies and transparent proxies. And they have different purposes, for example caching, load balancing, securing, monitoring, filtering, bypassing, and anonymizing. Proxies may require authentication.

An explicit web proxy is for example when you set your browser to use a proxy at a certain host and port number. With that proxy, the client makes an HTTP request to the proxy using the CONNECT method, then the proxy establishes a TCP connection to the destination server, and then the proxy acts as a blind tunnel that is forwarding TCP between client and server, seeing only the SSL/TLS handshake and then encrypted traffic.

You can test HTTP over SSL/TLS via an explicit proxy,

with cURL and Fiddler:

curl --verbose --cacert cacert.pem --proxy 127.0.0.1:8888 https://www.example.com/

with proxy authentication:

curl --verbose --cacert cacert.pem --proxy http://username:password@proxy:port/ https://www.example.com/

with GNU Wget and Fiddler:

export https_proxy=localhost:8888
wget --debug --https-only https://www.example.com:443/

You will see this request and response between client and proxy, then the SSL/TLS handshake, then the HTTP traffic:

CONNECT www.example.com:443 HTTP/1.1
Host: www.example.com:443
HTTP/1.1 200 Connection Established

On the other hand, a transparent proxy intercepts the traffic at the lower network level without requiring any client configuration. It acts as the SSL termination for the client, and establishes a second encryption channel with the destination server thereby being able to monitor and filter the SSL/TLS traffic in transit; in that case the client is not aware of the presence of the proxy but must trust the proxy’s certificate, and the proxy must trust the server’s certificate.

For MEC

In our case, we want MEC to communicate with partners over a secure channel with confidentiality, integrity, and authentication to protect the data being exchanged, optionally via proxy.

Problem

MEC does not provide secure channels for HTTP out of the box. For instance, there are no HTTPSIn, HTTPSOut, HTTPSSyncIn, or HTTPSSyncOut channels. There is an HTTPSOut channel, but it is only a sample in an appendix of the documentation (does that mean it is safe to use?), and it does not come out of the box in the Partner Admin, it must be added manually (although it is available in the Java library). Also, there is a WebServiceSyncIn channels that uses WS-Security specifically for XML over SOAP, but in my case I am interested in HTTPS in general, for example for flat files, I am not interested in SOAP. Ideally, I would prefer to use the Infor Grid which already communicates via HTTPS, but unfortunately it does not have a native connection handler for MEC.

None of this means MEC is insecure, it just means you have to add the security yourself.

Documentation

The useful documentation

The MEC Partner Admin Tool User Guide contains the necessary source code and some explanation for the HTTPSOut channel and user interface:

The obstructing documentation

However, the documentation references HTTPS Communication, HttpServer.xml, and HTTPSOut at the same time, yet it does not clearly explain the relationship between them, so it is confusing:

I had to find the Communication Plug-in Development User Guide of an old version of MEC to find the answer. It turns out the HttpServer.xml was a file that existed in old versions of MEC to configure the web user interface. I think the sample in the documentation used that server to test the HTTPSOut channel; I do not know. Anyway, that file does not exist anymore after MEC was ported to the Infor Grid, so that chapter is irrelevant, confusing, and unrelated to HTTPSOut. We can ignore it, and Infor should remove it from the Partner Admin guide.

Java classes

The MEC Java library ec-core-x.y.z.jar includes the Java classes sample.HTTPSOut and sample.HTTPSOutPanel:

Features

Looking at the source code, the HTTPSOut channel is similar to the HTTPOut channel: they both make a POST HTTP request to a destination server, at a host, port number, and path defined in the Partner Admin, with the message sent in the request body.

HTTPSOut uses javax.net.ssl.HttpsURLConnection which in turn uses javax.net.ssl.SSLSocket to establish a secure socket with the destination server. From the HTTPSOut point of view, it just reads/writes plain HTTP to the socket, and the socket underneath takes care of the handshake and encryption/decryption.

HTTPSOut has an advantage over HTTPOut. Given the entire HTTP traffic is encrypted over SSL/TLS, we can safely set a username and password for HTTP Basic authentication, unlike with HTTPOut where we should not set a username and password because they transit in clear text (trivial Base64 decode).

Drawbacks

HTTPOut and HTTPSOut share the same drawbacks: they do not use Java NIO, and there are no proxy settings.

HTTPSOut has additional drawbacks: there are no settings for Content-type, multi-part, and keep alive, unlike HTTPOut. Worse, the response is completely ignored unlike HTTPOut where the response is at least added to the debug log.

Test

You can test the HTTPSOut class with the following code and with a message.txt file:

javac -cp log4j-1.2.17.jar;ec-core-11.4.1.0.0.jar;. Test.java
java -cp log4j-1.2.17.jar;ec-core-11.4.1.0.0.jar;. Test < message.txt

import java.util.Properties;
import sample.HTTPSOut;

public class Test {
    public static void main(String[] args) throws Exception {
        Properties props = new Properties();
        props.setProperty(HTTPSOut.HOST, "www.example.com");
        props.setProperty(HTTPSOut.PORT, "443");
        props.setProperty(HTTPSOut.PATH, "/");
        props.setProperty(HTTPSOut.USER, "username");
        props.setProperty(HTTPSOut.PASSWORD, "*****");
        props.setProperty(HTTPSOut.TRUST_STORE, "C:\\somewhere\\keystore");
        props.setProperty(HTTPSOut.TRUST_STORE_PWD, "*****");
        HTTPSOut client = new HTTPSOut();
        client.send(System.in, null, props);
    }
}

HTTPSOut will send the following request over SSL/TLS:

POST /Hello HTTP/1.1
Content-Type: multipart/form-data; boundary=----------------------------afatudbu6sb5-875oo9dmn52fzfypuig0x1kv
Authorization: Basic: dXNlcm5hbWU6cGFzc3dvcmQ=
User-Agent: M3 Enterprise Collaborator v11.4.1.0
Cache-Control: no-cache
Pragma: no-cache
Host: www.example.com:443
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
Content-Length: 256
------------------------------afatudbu6sb5-875oo9dmn52fzfypuig0x1kv
Content-Disposition: form-data; name="name"; filename="output.xml"
Content-Type: application/xml

Hello, World!
------------------------------afatudbu6sb5-875oo9dmn52fzfypuig0x1kv--

Activity diagram

Here is a sample activity diagram of the HTTPSOut channel:

Authentication bug

There is a bug in the HTTPSOut class regarding the HTTP Basic authentication header that will cause the server to return HTTP/1.1 401 Unauthorized, and that is easy to fix:

// incorrect
urlConn.setRequestProperty("Authorization: Basic", Base64.encode (to64, "ISO-8859-1"));
// correct
urlConn.setRequestProperty("Authorization", "Basic " + Base64.encode (to64, "ISO-8859-1"));

The bug is located in both the HTTPSOut source code in the Partner Admin guide, and in the HTTPSOut class in the JAR file. And the JAR file is located in both the Partner Admin tool and in the MEC server in the Infor Grid.

That code is only executed if you need HTTP Basic authentication (i.e. if you specify a username and password); you can ignore it otherwise.

Proxy

If you need to use a proxy, add the following code to the HTTPSOut class and recompile it:

import java.net.Authenticator;
import java.net.InetSocketAddress;
import java.net.PasswordAuthentication;
import java.net.Proxy;

[...]
// get the proxy properties
String proxyHost = props.getProperty(PROXY_HOST);
int proxyPort = Integer.parseInt(props.getProperty(PROXY_PORT));
String proxyUser = props.getProperty(PROXY_USER);
String proxyPassword = props.getProperty(PROXY_PASSWORD);

// connect via proxy
InetSocketAddress proxyInet = new InetSocketAddress(proxyHost, proxyPort);
Proxy proxy = new Proxy(Proxy.Type.HTTP, proxyInet);
HttpsURLConnection con = (HttpsURLConnection) url.openConnection(proxy);

// authenticate to proxy
Authenticator.setDefault(new Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(proxyUser, proxyPassword.toCharArray());
    }
});

//con.setRequestProperty("Proxy-Authorization", "Basic " + Base64.encode(proxyUser + ":" + proxyPassword, "ISO-8859-1")); // this did not work for me

You will need to add some if-then-else so the user can choose to use a proxy or not, and add some exception handling around parseInt.

Also, for the user interface, you will need to add a group widget, a checkbox, four labels and four text boxes to the HTTPSOutPanel class and recompile it:

✗Security holes

Unfortunately, the HTTPSOut class does not verify the certificate and as such the connection is susceptible to man-in-the-middle attack.

For instance, it does not verify the hostname of the certificate, it just returns true for any hostname:

HostnameVerifier hv = new HostnameVerifier() {
    public boolean verify(String s, SSLSession sslSession) {
        return true;
    }
};

More so, HTTPSOut does not verify the certificate’s dates, revocation, basic constraint, extensions, etc.

Thus, HTTPSOut is not safe to use out of the box. You have to implement certificate validation yourself. That is probably why it is only a sample.

Compilation

To compile the HTTPSOut and HTTPSOutPanel classes:

1. Recover the source code (either copy/paste it from the Partner Admin guide, or decompile the classes).
2. Change the code as needed (e.g. fix the authentication bug, add the proxy settings, add certificate validation, etc.)
3. Compile the source code with:
   javac -cp lib\log4j-1.2.17.jar;lib\ec-core-11.4.1.0.0.jar sample\HTTPSOut.java
   javac -cp lib\x86-3.3.0-v3346.jar;lib\log4j-1.2.17.jar;lib\ec-core-11.4.1.0.0.jar;. sample\HTTPSOutPanel.java
   
4. Replace the Java classes in both the Partner Admin tool folder and in the MEC server folder of the Infor Grid, for example:
   D:\Infor\MECTOOLS\Partner Admin\classes\sample\
   D:\Infor\LifeCycle\host\grid\M3_Development\grids\M3_Development\applications\MECSRVDEV\MecServer\lib\sample\
   
5. Restart the Partner Admin and restart the MEC server in the Infor Grid.
6. The class loader will give precedence to the classes you put in the folders over the classes in the JAR file.

1. Preparation

Before we can use HTTPSOut, we have to prepare the terrain for SSL/TLS.

As a reminder, the HTTPSOut channel is an HTTP client that will make an HTTP request to a destination HTTP server over SSL/TLS, e.g. to https://www.example.com/.

1.1. Server authentication

The short instructions to setup server authentication are:

openssl s_client -connect www.example.com:443 > example.cer
keytool.exe -import -file example.cer -keystore example.ks -storepass changeit

The long instructions are the following.

We need to setup server authentication, i.e. for HTTPSOut to affirm the identity of the server it is connecting to; it will rely on SSLSocket to verify that the server certificate is signed by a certificate authority that is stored in a trusted keystore.

Internet Explorer, Google Chrome, Fiddler and other programs that use WinINet ultimately rely on the Windows certificate manager, certmgr.msc, but Firefox and Java each use their own key management. The JRE has its default keystore at %JAVA_HOME%\lib\security\cacerts that SSLSocket uses. HTTPSOut ignores the default keystore and requires the user to specify one. To create a Java keystore we use keytool.exe and import the server’s certificate in it.

The steps are:

1. Open a browser to the destination server over HTTPS and open the certificate:
   
2. Inspect the certificate, any intermediate certificate authorities, and the root certificate authority, up the chain, and make sure you trust them (if your browser does not trust them it will throw a big warning sign):
    
3. Now we need Java to trust that certificate. Check if one of the certificates in the chain is already in your Java keystore. Java already comes with a list of trusted certificates in its keystore. If the destination server presents a certificate that is already trusted by one of the trusted certificates of the JRE, it will automatically be trusted by the JRE, i.e. the friends of my friends are my friends. In my case, my JVM already trusts the certificate authority DigiCert, so by chain of trust it will automatically trust the certificate presented by http://www.example.com. It may be the same case for you:

   keytool.exe -list -keystore cacerts -storepass changeit | findstr /i DigiCert
   keytool.exe -list -keystore cacerts -storepass changeit -v -alias digicerthighassuranceevrootca

   

4. If you already have the server certificate, good, just keep in mind the location of that keystore, and skip the rest of these steps; otherwise continue reading.
5. Export the certificate to a file, e.g. example.cer:
   
6. Import the certificate to a keystore, e.g. example.ks:

   keytool.exe -import -file example.cer -keystore example.ks -storepass changeit

   

7. Now you have a keystore ready for HTTPSOut.

1.2. Client authentication

As for client authentication, the HTTPSOut channel does not support that, i.e. it does not have a public/private keys and a digital certificate to present to the server if the server requests it, so we have to forget about that. If the server needs to authenticate the client, we can use Basic authentication (provided we fix the authentication bug).

2. How to setup

Now let’s setup the HTTPSOut channel in MEC.

The steps will be:

1. Setup the Send protocol
2. Setup the Send channel configuration
3. Setup the Agreement with detection and processes

2.1. Setup the Send protocol

1. Open the Partner Admin tool
2. Go to Manage > Advanced
3. Select the Send Protocols tab
4. Click New, and set:
   Protocol: HTTPSOut
   Send class: sample.HTTPSOut
   UI class: sample.HTTPSOutPanel
   
5. Click OK
6. Click Close

2.2. Setup the Send channel configuration

1. Go to Manage > Communications
2. Select the Send tab
3. Click New:
   
4. Select protocol HTTPSOut and enter the information host, port number and path to the destination server, as well as the keystore where you saved the certificate and the keystore password, and optionally set user and password for HTTP Basic authentication to the destination server (provided you corrected the authentication bug):
   
   Note: The keystore path is relative to the JVM that runs MEC server, i.e. java.exe must be able to access the file and have read permission to it. Also, given the Infor Grid is distributed make sure the keystore file is distributed accordingly to the correct server.
5. Optionally set the proxy settings if you added that feature to the classes (see proxy section above)
6. Click Send test message to ensure everything is correct; if you get an error message, test the HTTPSOut class as explained in the test section above, or check the troubleshooting tips in the section below
7. Click OK
8. Click Close

2.3. Setup the Agreement with detection and processes

1. In Communications > Receive, setup any incoming channel such that we can simply trigger the partner agreement for the purposes of illustration; the protocol is not important right now; for instance I have a simple DiskIn channel that has status RUNNING in my Infor Grid, and I have a partner agreement with it in a channel detection.
2. Go the agreement > Processes, right-click select Send, and select the HTTPSOut channel:
   
3. Click OK
4. Click Save
5. The HTTPSOut channel is now ready to use

3. How to test

To test the HTTPSOut channel, follow the same instructions as in the test of Part 4.

4. …on the Internet

If you are doing the HTTPS requests to a server out on the Internet you should consult with your security team. I have MEC in a LAN behind a NAT, firewall, content based filter, security appliance, and transparent proxy.

5. Troubleshooting

In case HTTPSOut does not work as expected, here are some troubleshooting tips.

Check the logs

The MEC server logs are useful for troubleshooting problems. For example, in one case I got the following exception:

sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

That means the server certificate validation failed, either because we put the incorrect server certificate in the keystore that we defined in PartnerAdmin, either because a man-in-the-middle server presented a different certificate.

Test SSL/TLS connection

Some network and security administrators setup firewalls, proxies, and gateways that interfere with SSL/TLS. In my case, I will ensure that my host can access the destination server over SSL/TLS. For that:

1. Locate on which node is MEC server running:
   
2. From that server (for example via Remote Desktop Connection), make a test connection to the destination server over SSL/TLS, for example use OpenSSL s_client:

   openssl s_client -connect www.example.com:443 -showcerts

3. Make sure the server certificate that is presented is the correct one.

Test HttpsURLConnection

1. Check what JVM the MEC server is using:
   
2. Use that JVM to test a HttpsURLConnection; that will check if that particular JVM of that host has access to read that keystore, it will check if it can make a SSL/TLS connection to that destination server, and it will show the server certificates received:

   // javac Test.java && java -cp . Test
   
   import java.io.OutputStream;
   import java.net.URL;
   import java.security.cert.Certificate;
   import javax.net.ssl.HttpsURLConnection;
   
   public class Test {
       public static void main(String[] args) throws Exception {
           System.setProperty("javax.net.ssl.trustStore", "D:\\java\\jre\\lib\\security\\cacerts");
           System.setProperty("javax.net.ssl.trustStorePassword", "changeit");
           URL url = new URL("https://www.example.com/");
           HttpsURLConnection con = (HttpsURLConnection) url.openConnection();
           con.setDoOutput(true);
           OutputStream out = con.getOutputStream();
           Certificate[] scerts = con.getServerCertificates();
           for (Certificate scert: scerts) {
               System.out.println(scert.toString());
           }
           con.disconnect();
       }
   }
   

Test HTTPSOut

See the section at the top to test the HTTPSOut class.

Conclusion

That was an illustration of how to setup the HTTPSOut channel in MEC so that MEC can act as a client making secure HTTP requests to servers over SSL/TLS. For that, we reviewed the basics of HTTPS, we reviewed the features and drawbacks of HTTPSOut, we learned how to fix the authentication bug, how to add proxy settings, we identified security holes, we learned how to recompile the classes, how to setup the channel in PartnerAdmin, how to test, and how to troubleshoot.

HTTPSOut lacks features, it has a bug, and it has security holes; that is probably why it is just considered a sample channel that is unsafe to use in a production environment. Take it as a starting point from which you can build your own safe channel with production quality.

Hopefully, Infor will remove the deprecated documentation from the Partner Admin guide, will enhance the HTTPSOut channel from unsafe sample to safe channel with production quality, and will eventually provide a native connection handler in the Infor Grid for MEC.

In the next part of this guide, I will illustrate how to setup HTTPS for inbound messages.

(Congratulations if you made it this far! Let me know what you think in the comments below.)

Related articles

• HTTP channels in MEC (part 1)
• HTTP channels in MEC (part 2)
• HTTP channels in MEC (part 3)
• HTTP channels in MEC (part 4)