Posts Tagged ‘certificate’

Improve SSL security: Generate and add Diffie Hellman key to SSL certificate for stronger line encryption

Wednesday, June 10th, 2020

Diffie–Hellman key exchange (DH) is a method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman. DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography.

Traditionally, secure encrypted communication between two parties required that they first exchange keys by some secure physical means, such as paper key lists transported by a trusted courier. The Diffie–Hellman key exchange method allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure channel. This key can then be used to encrypt subsequent communications using a symmetric key cipher.

DH has been widely used on the Internet for improving the authentication encryption among parties. The only note is it useful if both the communication sides A and B are at your control, as what DH does is just strenghten the already established connection between client A and B and not protect from Man in the Middle Attacks. If some malicious user could connect to B pretending it is A the encryption will be established.

diffie-hellman-explained

Alternatively, the Diffie-Hellman key exchange can be combined with an algorithm like the Digital Signature Standard (DSS) to provide authentication, key exchange, confidentiality and check the integrity of the data. In such a situation, RSA is not necessary for securing the connection.

TLS, which is a protocol that is used to secure much of the internet, can use the Diffie-Hellman exchange in three different ways: anonymous, static and ephemeral. In practice, only ephemeral Diffie-Hellman should be implemented, because the other options have security issues.

Anonymous Diffie-Hellman – This version of the Diffie-Hellman key exchange doesn’t use any authentication, leaving it vulnerable to man-in-the-middle attacks. It should not be used or implemented.

Static Diffie-Hellman – Static Diffie-Hellman uses certificates to authenticate the server. It does not authenticate the client by default, nor does it provide forward secrecy.

Ephemeral Diffie-Hellman – This is considered the most secure implementation because it provides perfect forward secrecy. It is generally combined with an algorithm such as DSA or RSA to authenticate one or both of the parties in the connection.

Ephemeral Diffie-Hellman uses different key pairs each time the protocol is run. This gives the connection perfect forward secrecy, because even if a key is compromised in the future, it can’t be used to decrypt all of the past messages.

diffie-hellman-dh-revised

DH encryption key could be generated with the openssl command and could be generated depending on your preference using a 1024 / 2048 or 4096 bit encryption.
Of course it is best to have the strongest encryption possible i.e 4096.

The Logjam attack 

The Diffie-Hellman key exchange was designed on the basis of the discrete logarithm problem being difficult to solve. The most effective publicly known mechanism for finding the solution is the number field sieve algorithm.

The capabilities of this algorithm were taken into account when the Diffie-Hellman key exchange was designed. By 1992, it was known that for a given group, G, three of the four steps involved in the algorithm could potentially be computed beforehand. If this progress was saved, the final step could be calculated in a comparatively short time.

This wasn’t too concerning until it was realized that a significant portion of internet traffic uses the same groups that are 1024 bits or smaller. In 2015, an academic team ran the calculations for the most common 512-bit prime used by the Diffie-Hellman key exchange in TLS.

They were also able to downgrade 80% of TLS servers that supported DHE-EXPORT, so that they would accept a 512-bit export-grade Diffie-Hellman key exchange for the connection. This means that each of these servers is vulnerable to an attack from a well-resourced adversary.

The researchers went on to extrapolate their results, estimating that a nation-state could break a 1024-bit prime. By breaking the single most-commonly used 1024-bit prime, the academic team estimated that an adversary could monitor 18% of the one million most popular HTTPS websites.

They went on to say that a second prime would enable the adversary to decrypt the connections of 66% of VPN servers, and 26% of SSH servers. Later in the report, the academics suggested that the NSA may already have these capabilities.

“A close reading of published NSA leaks shows that the agency’s attacks on VPNs are consistent with having achieved such a break.”

Despite this vulnerability, the Diffie-Hellman key exchange can still be secure if it is implemented correctly. As long as a 2048-bit key is used, the Logjam attack will not work. Updated browsers are also secure from this attack.

Is the Diffie-Hellman key exchange safe?

While the Diffie-Hellman key exchange may seem complex, it is a fundamental part of securely exchanging data online. As long as it is implemented alongside an appropriate authentication method and the numbers have been selected properly, it is not considered vulnerable to attack.

The Diffie-Hellman key exchange was an innovative method for helping two unknown parties communicate safely when it was developed in the 1970s. While we now implement newer versions with larger keys to protect against modern technology the protocol itself looks like it will continue to be secure until the arrival of quantum computing and the advanced attacks that will come with it.

Here is how easy it is to add this extra encryption to make the SSL tunnel between A and B stronger.

On a Linux / Mac / BSD OS machine install and use openssl client like so:
 

# openssl dhparam -out dhparams1.pem 2048
Generating DH parameters, 2048 bit long safe prime, generator 2
This is going to take a long time
……………………………………………………….+………..+………………………………………………………+


…..
…. ………………..++*++*

Be aware that the Diffie-Hellman key exchange would be insecure if it used numbers as small as those in our example. We are only using such small numbers to demonstrate the concept in a simpler manner.

 

# cat dhparams1.pem
—–BEGIN DH PARAMETERS—–
MIIBCAKCAQEAwG85wZPoVAVhwR23H5cF81Ml4BZTWuEplrmzSMOR9UNMnKjURf10
JX9xe/ZaqlwMxFYwZLyqtFQB2zczuvp1j+tKkSi4/TbD6Qm6gtsTeRghqunfypjS
+c4dNOVSbo/KLuIB5jDT31iMUAIDJF8OBUuqazRsg4pmYVHFm1KLHCcgcTk5kXqh
m8vXoCTlaLlmicC9pRTgQLuAQRXAF8LnVLCUvGlsyynTdc0yUFePWkmeYHMYAmWo
aBS6AMFNDvOxCubWv9cULkOouhPzd8k0wWYhUrrxMJXc1bSDFCBA7DiRCLPorefd
kCcNJFrh7rgy1lmu00d3I5S9EPH/EyoGSwIBAg==
—–END DH PARAMETERS—–


Copy the generated DH PARAMETERS headered key string to your combined .PEM certificate pair at the end of the file and save it

 

# vim /etc/haproxy/cert/ssl-cert.pem
….
—–BEGIN DH PARAMETERS—–
MIIBCAKCAQEAwG85wZPoVAVhwR23H5cF81Ml4BZTWuEplrmzSMOR9UNMnKjURf10
JX9xe/ZaqlwMxFYwZLyqtFQB2zczuvp1j+tKkSi4/TbD6Qm6gtsTeRghqunfypjS
+c4dNOVSbo/KLuIB5jDT31iMUAIDJF8OBUuqazRsg4pmYVHFm1KLHCcgcTk5kXqh
m8vXoCTlaLlmicC9pRTgQLuAQRXAF8LnVLCUvGlsyynTdc0yUFePWkmeYHMYAmWo
aBS6AMFNDvOxCubWv9cULkOouhPzd8k0wWYhUrrxMJXc1bSDFCBA7DiRCLPorefd
kCcNJFrh7rgy1lmu00d3I5S9EPH/EyoGSwIBAg==
—–END DH PARAMETERS—–

…..

Restart the WebServer or Proxy service wher Diffie-Hellman key was installed and Voila you should a bit more secure.

 

 

Create and Configure SSL bundle file for GoGetSSL issued certificate in Apache Webserver on Linux

Saturday, November 3rd, 2018

gogetssl-install-certificate-on-linux-howto-sslcertificatechainfile-obsolete

I had a small task to configure a new WildCard SSL for domains on a Debian GNU / Linux Jessie running Apache 2.4.25.

The official documentation on how to install the SSL certificate on Linux given by GoGetSSL (which is by COMODO was obsolete as of time of writting this article and suggested as install instructions:
 

SSLEngine on
SSLCertificateKeyFile /etc/ssl/ssl.key/server.key
SSLCertificateFile /etc/ssl/ssl.crt/yourDomainName.crt
SSLCertificateChainFile /etc/ssl/ssl.crt/yourDomainName.ca-bundle


Adding such configuration to domain Vhost and testing with apache2ctl spits an error like:

 

root@webserver:~# apache2ctl configtest
AH02559: The SSLCertificateChainFile directive (/etc/apache2/sites-enabled/the-domain-name-ssl.conf:17) is deprecated, SSLCertificateFile should be used instead
Syntax OK

 


To make issued GoGetSSL work with Debian Linux, hence, here is the few things done:

The files issued by Gogetssl.COM were the following:

 

AddTrust_External_CA_Root.crt
COMODO_RSA_Certification_Authority.crt
the-domain-name.crt


The webserver had already SSL support via mod_ssl Apache module, e.g.:

 

root@webserver:~# ls -al /etc/apache2/mods-available/*ssl*
-rw-r–r– 1 root root 3112 окт 21  2017 /etc/apache2/mods-available/ssl.conf
-rw-r–r– 1 root root   97 сеп 19  2017 /etc/apache2/mods-available/ssl.load
root@webserver:~# ls -al /etc/apache2/mods-enabled/*ssl*
lrwxrwxrwx 1 root root 26 окт 19  2017 /etc/apache2/mods-enabled/ssl.conf -> ../mods-available/ssl.conf
lrwxrwxrwx 1 root root 26 окт 19  2017 /etc/apache2/mods-enabled/ssl.load -> ../mods-available/ssl.load


For those who doesn't have mod_ssl enabled, to enable it quickly run:

 

# a2enmod ssl


The VirtualHost used for the domains had Apache config as below:

 

 

 

NameVirtualHost *:443

<VirtualHost *:443>
    ServerAdmin support@the-domain-name.com
    ServerName the-domain-name.com
    ServerAlias *.the-domain-name.com the-domain-name.com

    DocumentRoot /home/the-domain-namecom/www
    SSLEngine On
#    <Directory />
#        Options FollowSymLinks
#        AllowOverride None
#    </Directory>
    <Directory /home/the-domain-namecom/www>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride None
        Include /home/the-domain-namecom/www/htaccess_new.txt
        Order allow,deny
        allow from all
    </Directory>

    ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
    <Directory "/usr/lib/cgi-bin">
        AllowOverride None
        Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
        Order allow,deny
        Allow from all
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error.log

    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn

    CustomLog ${APACHE_LOG_DIR}/access.log combined

#    Alias /doc/ "/usr/share/doc/"
#   <Directory "/usr/share/doc/">
#       Options Indexes MultiViews FollowSymLinks
#       AllowOverride None
#       Order deny,allow
#       Deny from all
#       Allow from 127.0.0.0/255.0.0.0 ::1/128
#   </Directory>
SSLCertificateKeyFile /etc/apache2/ssl/the-domain-name.com.key
SSLCertificateFile /etc/apache2/ssl/chain.crt

 

</VirtualHost>

The config directives enabling and making the SSL actually work are:
 

SSLEngine On
SSLCertificateKeyFile /etc/apache2/ssl/the-domain-name.com.key
SSLCertificateFile /etc/apache2/ssl/chain.crt

 

The chain.crt file is actually a bundle file containing a bundle of the gogetssl CA_ROOT and RSA_Certification_Authority 3 files, to prepare that file, I've used bundle.sh small script found on serverfault.com here I've made a mirror of bundle.sh on www.pc-freak.net here   the script content is as follows:

To prepare the chain.crt  bundle, I ran:

 

sh create-ssl-bundle.sh _iq-test_cc.crt chain.crt
sh create-ssl-bundle.sh _iq-test_cc.crt >chain.crt
sh create-ssl-bundle.sh COMODO_RSA_Certification_Authority.crt >> chain.crt
sh create-ssl-bundle.sh bundle.sh AddTrust_External_CA_Root.crt >> chain.crt


Then I copied the file to /etc/apache2/ssl together with the-domain-name.com.key file earlier generated using openssl command earlier explained in my article how to install RapidSSL certificate on Linux

/etc/apache2/ssl was not previously existing (on Debian Linux), so to create it:

 

root@webserver:~# mkdir /etc/apache2/ssl
root@webserver:~# ls -al /etc/apache2/ssl/chain.crt
-rw-r–r– 1 root root 20641 Nov  2 12:27 /etc/apache2/ssl/chain.crt
root@webserver:~# ls -al /etc/apache2/ssl/the-domain-name.com.key
-rw-r–r– 1 root root 6352 Nov  2 20:35 /etc/apache2/ssl/the-domain-name.com.key

 

As I needed to add the SSL HTTPS configuration for multiple domains, further on I've wrote and used a tiny shell script add_new_vhost.sh which accepts as argument the domain name I want to add. The script works with a sample Skele (Template) file, which is included in the script itself and can be easily modified for the desired vhost config.
To add my multiple domains, I've used the script as follows:
 

sh add_new_vhost.sh add-new-site-domain.com
sh add_new_vhost.sh add-new-site-domain1.com


etc.

Here is the complete script as well:

 

#!/bin/sh
# Shell script to add easily new domains for virtual hosting on Debian machines
# arg1 should be a domain name
# This script takes the domain name which you type as arg1 uses it and creates
# Docroot / cgi-bin directory for the domain, create seperate site's apache log directory
# then takes a skele.com file and substitutes a skele.com with your domain name and directories
# This script's aim is to easily enable sysadmin to add new domains in Debian
sites_base_dir=/var/www/jail/home/www-data/sites/;
# the directory where the skele.com file is
skele_dir=/etc/apache2/sites-available;
# base directory where site log dir to be created
cr_sep_log_file_d=/var/log/apache2/sites;
# owner of the directories
username='www-data';
# read arg0 and arg1
arg0=$0;
arg1=$1;
if [[ -z $arg1 ]]; then
echo "Missing domain name";
exit 1;
fi

 

# skele template
echo "#
#  Example.com (/etc/apache2/sites-available/www.skele.com)
#
<VirtualHost *>
        ServerAdmin admin@design.bg
        ServerName  skele.com
        ServerAlias www.skele.com


        # Indexes + Directory Root.
        DirectoryIndex index.php index.htm index.html index.pl index.cgi index.phtml index.jsp index.py index.asp

        DocumentRoot /var/www/jail/home/www-data/sites/skelecom/www/docs
        ScriptAlias /cgi-bin "/var/www/jail/home/www-data/sites/skelecom/cgi-bin"
        
        # Logfiles
        ErrorLog  /var/log/apache2/sites/skelecom/error.log
        CustomLog /var/log/apache2/sites/skelecom/access.log combined
#       CustomLog /dev/null combined
      <Directory /var/www/jail/home/www-data/sites/skelecom/www/docs/>
                Options FollowSymLinks MultiViews -Includes
                AllowOverride None
                Order allow,deny
                allow from all
                # This directive allows us to have apache2's default start page
                # in /apache2-default/, but still have / go to the right place
#               RedirectMatch ^/$ /apache2-default/
        </Directory>

        <Directory /var/www/jail/home/www-data/sites/skelecom/www/docs/>
                Options FollowSymLinks ExecCGI -Includes
                AllowOverride None
                Order allow,deny
                allow from all
        </Directory>

</VirtualHost>
" > $skele_dir/skele.com;

domain_dir=$(echo $arg1 | sed -e 's/\.//g');
new_site_dir=$sites_base_dir/$domain_dir/www/docs;
echo "Creating $new_site_dir";
mkdir -p $new_site_dir;
mkdir -p $sites_base_dir/cgi-bin;
echo "Creating sites's Docroot and CGI directory";
chown -R $username:$username $new_site_dir;
chown -R $username:$username $sites_base_dir/cgi-bin;
echo "Creating site's Log files Directory";
mkdir -p $cr_sep_log_file_d/$domain_dir;
echo "Creating sites's VirtualHost file and adding it for startup";
sed -e "s#skele.com#$arg1#g" -e "s#skelecom#$domain_dir#g" $skele_dir/skele.com >> $skele_dir/$arg1;
ln -sf $skele_dir/$arg1 /etc/apache2/sites-enabled/;
echo "All Completed please restart apache /etc/init.d/apache restart to Load the new virtual domain";

# Date Fri Jan 11 16:27:38 EET 2008


Using the script saves a lot of time to manually, copy vhost file and then edit it to change ServerName directive, for vhosts whose configuration is identical and only the ServerName listener has to change, it is perfect to create all necessery domains, I've created a simple text file with each of the domains and run it in a loop:
 

while :; do sh add_new_vhost.sh $i; done < domain_list.txt
 

 

Fix “Secure Connection Failed” – An error occured SSL received a record that exceeded the maximum permissible length howto

Monday, September 14th, 2015

secure-connection-failed-an-error-occured-during-connection-ssl-received-a-record-that-exceeds-the-maximum-permissible-length-fix-howto
When I was trying to establish a new Internal Business SSL certificate on one of the 6 months planned SPLIT projects (e.g. duplicate a range systems environment to another one), I've stumbled a very odd SSL issue. Once I've setup all the virtualhost SSL configurations properly (identical SSL configuration directives and Apache Webserver version to another host and testing in a browser I was getting the following error:
 

Secure Connection Failed

An error occurred during a connection to 10.253.39.93.

SSL received a record that exceeded the maximum permissible length.

(Error code: ssl_error_rx_record_too_long)


Below is a screenshot:

https://www.pc-freak.net/images/secure-connection-failed-an-error-occured-during-connection-ssl-received-a-record-that-exceeds-the-maximum-permissible-length.png

The page you are trying to view can not be shown because the authenticity of the received data could not be verified. Please contact the web site owners to inform them of this problem. Alternatively, use the command found in the help menu to report this broken site.

The first logical thing to do was to check the error.log but there was no any errors there that point me to anything meaningful, besides that the queries I was making to the Domain doesn't show off as requests neither in Apache access.log nor in error.log so this was puzzling.
I thought I might have messed up something during Key file / CSR generation time so I revoked old certificate and reissued it.

 

$ openssl x509 -text -in test-pegasusgas-eon.intranet.eon-vertrieb.com.crt |less ertificate: Data: Version: 3 (0x2) Serial Number:

Shows that all is fine with certificate Then when trying to test remote certificate with SSL command:

 

openssl s_client -CApath test-pegasusgas-eon.intranet.eon-vertrieb.com.crt -connect test-pegasusgas-eon.intranet.eon-vertrieb.com:443


: There was an error After plenty of research in Google I come to conclusion something is either wrong with Listen httpd.conf directive or NameVirtualHost is binded to port 80 or some other port different from 443, however surprisingly I did not used the NameVirtualHost at all in my apache config. After a lot of pondering I finally spot it. The whole certificate isseus were caused by:

< – Less than sign

which I missaw and forget to clean up from template during IP paste (obtained from /sbin/ifconfig |grep -i xx.xx.xx.xx). So finally in order to fix the SSL error I had to just delete <, e.g.:
 

<VirtualHost <10.253.39.35:443>

had to become:

 

<Virtualhost 10.253.39.35:443>

Such a minor thing took me 3 hours of pondering to resolve and thanksfully it is finally fixed! Then of course had to restart Apache to make fixed Vhost settings working:
 

# apachectl stop; sleep 2; apachectl start

So now the SSL works again, thanks God!

Weblogic – How to change / remove IP/hostname quick and dirty howto

Wednesday, March 11th, 2015

Oracle-Weblogic-Server-logo-how-to-change-ip-hostname-weblogic-quick-and-dirty-howto

This is just quick & dirty doc on how to change/remove IP/host on Oracle WebLogic Application server

– In logs the Error message will be message like:

 

<Oct 21, 2013 1:06:51 AM SGT> <Warning> <Security> <BEA-090504> <Certificate chain received from cluster2.yourdomain.com – 192.168.1.41 failed hostname verification check. Certificate contained cluster1.yourdomain.com but check expected cluster2.yourdomain.com>

 

 

Solution:

On web console – change/remove IP/hostname

 

As root / admin supersuser:

 

– Stop Weblogic Webserver 

As this is RHEL Linux, to stop WLS use standard init script start / stop service command

 

service wls stop

 

– As Application user create directory where new key will be created

 

mkdir /home/uwls11pp/tmp_key
cd /home/uwls11pp/tmp_key

 

– Make backup of current JKS (Keystore File)

 

cp /WLS/app/oracle/wls1036/wlserver_10.3/server/lib/DemoIdentity.jks /WLS/app/oracle/wls1036/wlserver_10.3/server/lib/DemoIdentity.jks_11032015

 

– Execute set env . script

 

/WLS/app/oracle/wls1036/wlserver_10.3/server/bin/setWLSEnv.sh

 

– Copy & paste output from script above and export variables

 

export CLASSPATH;
export PATH;

 

– Check old certificate in keystore

 

/WLS/app/oracle/jdk1.7.0_25/bin/keytool -list -v -keystore /WLS/app/oracle/wls1036/wlserver_10.3/server/lib/DemoIdentity.jks  -storepass DemoIdentityKeyStorePassPhrase

 

– Delete old Weblogic keystore JKS file

 

/WLS/app/oracle/jdk1.7.0_25/bin/keytool -delete -alias demoidentity -keystore /WLS/app/oracle/wls1036/wlserver_10.3/server/lib/DemoIdentity.jks -storepass DemoIdentityKeyStorePassPhrase

 

– Check wether proper Java version is used

 

java -version

 

– Get hostname from hosts file

 

cat /etc/hosts

 

#Replace weblogic1 with your FQDN (Fully Qualified Domain Name) – this step will create new certificate with new hostname

 

java utils.CertGen -cn weblogic1 -keyfilepass DemoIdentityPassPhrase -certfile newcert -keyfile newkey

 

#Import certificate to “official” keystore

 

java utils.ImportPrivateKey -keystore /WLS/app/oracle/wls1036/wlserver_10.3/server/lib/DemoIdentity.jks -storepass DemoIdentityKeyStorePassPhrase -keyfile newkey.pem -keyfilepass DemoIdentityPassPhrase -certfile newcert.pem -alias demoidentity

 

#Recheck once again if correct certificate is in use

 

/WLS/app/oracle/jdk1.7.0_25/bin/keytool -list -v -keystore /WLS/app/oracle/wls1036/wlserver_10.3/server/lib/DemoIdentity.jks  -storepass DemoIdentityKeyStorePassPhrase


– Finally issue as root user restart Weblogic server again

 

 

service wls start

Apache SSLCertificateChainFile adding SSL with Certificate Chain / What is Certificate Chain

Friday, January 31st, 2014

configure-apache-ssl-certificate-chain-ssl-certificate-keychain-each-signing-each-other

If you work in a big company with large network infrastructure who has to deal with SSL Certificates you will sooner or later will have to learn about existence of SSL Certificate Chains.
Its worthy thus to know what is SSL Certificate Chains and how such a chain is configured in Apache?

Personal SSL certificates (certificates issued to an individual or a company) can be used by clients to uniquely identify themselves when they are involved in starting an SSL connection.
SSL Certificate file contains X.509 certificate, which, in turn, contains a public key used for encryption.
Each personal certificate has zero or more certificate chains of certification authority certificates that extend back to the root certification authority.
 

Certificate R (Root Certification Authority)
    |
    | represents issuer of
    V
Certificate I1 (Intermediate Certification Authority)
    |
    | represents issuer of
    V
Certificate I2 (A subsidiary Intermediate Certification Authority)
    |
    | represents issuer of
    V
Certificate I3 (A further subsidiary Intermediate Certification Authority)
    |
    | represents issuer of
    V
Certificate P (A personal certificate that is used to identify its owner 
               on an SSL handshake)

Certificate chains are used to verify the authenticity of each certificate in that chain, including the personal certificate. Each certificate in the chain is validated using its 'parent' certificate, which in turn is validated using the next certificate up the chain, and so on, from the personal certificate up to the root certification authority certificate.

Now after explaining thoroughfully what is SSL Certificate Chain, here is how to configure a SSL Certificate in Apache Webserver.

Open apache2.conf or httpd.conf (depending on GNU / Linux distribution) and add to it;

  SSLEngine On
   SSLCertificateFile conf/cert/webserver-host.crt
   SSLCertificateKeyFile conf/cert/webserver-host.key
   SSLCertificateChainFile conf/cert/internet-v4.crt
   # SSLCertificateChainFile conf/cert/intranet-v3.crt
   SSLOptions +StdEnvVars +OptRenegotiate +ExportCertData

SSLCertificateChainFile conf/cert/chain-cert.crt
loads a chain of separate Personal SSL certificates each signing each other on different levels, chain is leading to top ROOT CA (Certificate Authority).

How to generate self signed SSL certificate with openssl on Linux / BSD

Wednesday, November 6th, 2013

How to generate self signed SSL certificate with openssl on Linux / BSD

It is common solution for personal use to generate SSL certificates which are self-signed. Self-signed certificates are dangerous as no authority or company guarantees that remote site is trustable. However for private use having encrypted connection whether you need to transfer personal data is better than not having such. There are plenty of tutorials online pointing how to set-up Apache webserver to provide access via SSL port 443 with self-signed certifacate, but anyways I decided to blog here a one-liner command way, which makes generating self-signed certificate a piece of cake. Self-signed certificates on UNIX are generated with openssl command part of openssl (Secure Socket Layer cryptocgraphic tools).

On Debian Linux to install openssl (if you still don't have it):

apt-get install --yes openssl

On Fedora, RHEL, CentOS etc. same install should be done with:

yum install -y openssl

On FreeBSD to install it use ports;

cd /usr/ports/security/openssl
make install clean

Once openssl is available, here is command to generate self signed SSL certitifacate;
 

openssl req -x509 -nodes -days 3650 -newkey rsa:2048 -keyout my-sitename.key -out my-sitename.crt
Generating a 2048 bit RSA private key
............................................+++
..............................................................+++
writing new private key to 'key.pem'
Enter PEM pass phrase:
Verifying - Enter PEM pass phrase:
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:BG
State or Province Name (full name) [Some-State]:Sofia
Locality Name (eg, city) []:Sofia
Organization Name (eg, company) [Internet Widgits Pty Ltd]:Pc Freak
Organizational Unit Name (eg, section) []:Pc Freak
Common Name (eg, YOUR name) []:www.pc-freak.net
Email Address []:testing@www.pc-freak.net



The generated certificate Private Key file is placed in my-sitename.key
, actual certificate is located in my-sitename.crt -days option tells for how long period certificate will be valid. Regenerating certificate every year (360 days) is good security practice but it is pretty annoying to see your certificate has expered thus for private self signed SSL certificate it is more confortable to generate cert for 10 years time.
To use my-sitename.key and my-sitename.crt copy them to /etc/ssl/crt/

cp -rpf my-sitename.crt /etc/ssl/crt/
cp -rpf my-sitename.key /etc/ssl/crt/

Next what's left is to configure Apache to use new generated certs. Quickest way is to add it inside virtual host. Adding to Apache also depends on Linux distribution where SSL has to be added but in general, what should work is something like:

SSLEngine on
SSLCertificateFile /etc/ssl/crt/my-sitename.crt
SSLCertificateKeyFile /etc/ssl/crt/my-sitename.key

Note that if SSL has to be enabled for specific Virtual Host you will have to place above Apache directives into the Vhost. Though certifiate will only be trusted by your authority RSA 2048 bit encryption in transfer data between your Webserver and Browser should guarantee you extra security of data, not that it is impossible for data to be still sniffed by a skilled hacker but makes data securily transferred in probably 99% of cases 🙂

Don’t revoke GoDaddy SSL certificate. (Expired) Revoked SSL is impossible to revert

Thursday, April 12th, 2012

godaddy_logo
One of our company SSL (https) Certificates recently expired so I needed to renew the SSL certificate.

I was in a hurry doing plenty of other stuffs so it seemed logical for me to Revoke the Certificate. I thought revoking the certificate will simply cancel it and afterwards, in Godaddy's SSL (Manager Certificates) interface the Revoked – Cancelled certificate will re-appear in the menu, ready to be generated in the same way as earlier I initially generated the Godaddy's bought SSL certificate

Hence I proceeded and used Revoke button:

Godaddy SSL certificate manager browser certificate Screenshot

Well guess what my calculations, were wrong.
 Revoking, just cancel it. The  revoked domain SSL certificate did not show up again in Godaddy's Cert Manager and I have no way from their interface to revert the changes.

To deal with the situation, I contacted Godaddy Support immediately with the following inquiry:
 

Other : Revoked SSL Certificate
Issue :
Hello we have revoked the SSL certificate for our domain our.domain-name.com.
 Can we revert back the certificate as it was.
If not how to generate a new key for our domain https://our.domain-name.com
Thanks in Advance.
Kindest Regards

"My-Company-name" Tech Support

In 5 hours time I received the following tech support answer:
 

Dear Tech Support,

Thank you for contacting Online Support. It is not possible to reinstate a canceled certificate. You will need to purchase a new certificate. I have requested that a refund be applied to your account. Once the credit appears in your account, please allow 5-7 business days to see the funds applied to the associated payment method. Thank you for your patience and understanding in this matter.

Please let us know if we can help you in any other way.

Sincerely,

Christian P.
Online Support Team
Customer Inquiry
Name : Cadia Tech Support
Domain Name : our.domain-name.com
ShopperID : xxxxxxxxx
Phone : xxxxxxxx
Shopper Validated : Yes
Browser : Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3

Apparently Godaddy, can work out a bit on their tech support answering time 5 hours for a simple reply is quite long.

Now taking in consideration, above reply from Godady, my only options are to either wait for 5 to 7 (business days) or buy a new credit for SSL certificate.

Buying a new credit will probably not happen as our company is experiencing some financial troubles because of the crisis. So I guess we will have to wait for this 7 days at worst. So again if you wonder to REVOKE or not an SSL certificate. Think again …

Just a small note to make here, that Godaddy has a very straight forward way to just renew an expered certificate, which I succesfully later have done for 4 domains. Well, if only I knew earlier what REVOKE SSL cert really does I wouldn't have ended in this mess …

How to fix “sslserver: fatal: unable to load certificate” Qmail error on GNU / Linux

Friday, October 14th, 2011

After setupping a brand new Qmail installation following the QmailRocks Thibs Qmail Debian install guide , I’ve come across unexpected re-occuring error message in /var/log/qmail/qmail-smtpdssl/ , here is the message:

@400000004e9807b10d8bdb7c command-line: exec sslserver -e -vR -l my-mailserver-domain.com -c 30 -u 89 -g 89
-x /etc/tcp.smtp.cdb 0 465 rblsmtpd -r zen.spamhaus.org -r dnsbl.njabl.org -r dnsbl.sorbs.net -r bl.spamcop.net qmail-smtpd
my-mailserver-domain.com /home/vpopmail/bin/vchkpw /bin/true 2>&1
@400000004e9807b10dae2ca4 sslserver: fatal: unable to load certificate

I was completely puzzled initially by the error as the sertificate file /var/qmail/control/servercert.pem was an existing and properly self generated one. Besides that qmail daemontools init script /service/qmail-smtpd/run was loading the file just fine, where the same file failed to get loaded when sslserver command with the cert argument was invoked via /service/qmail-smtpdssl/run

It took me quite a while to thoroughfully investigate on what’s wrong with the new qmail install. Thanksfully after almost an hour of puzzling I found it out and I was feeling as a complete moron to find that the all issues was caused by incorrect permissions of the /var/qmail/control/servercert.pem file.
Here are the incorrect permissions the file possessed:

linux:~# ls -al /var/qmail/control/servercert.pem
-rw------- 1 qmaild qmail 2311 2011-10-12 13:21 /var/qmail/control/servercert.pem

To fix up the error I had to allow all users to have reading permissions over servercert.pem , e.g.:

linux:~# chmod a+r /var/qmail/control/servercert.pem

After adding all users readable bit on servercert.pem the file permissions are like so:

linux:~# ls -al /var/qmail/control/servercert.pem
-rw-r--r-- 1 qmaild qmail 2311 2011-10-12 13:21 /var/qmail/control/servercert.pem

Consequently I did a qmail restart to make sure the new readable servercert.pem will get loaded from the respective init script:

linux:~# qmailctl restart
* Stopping qmail-smtpdssl.
* Stopping qmail-smtpd.
* Sending qmail-send SIGTERM and restarting.
* Restarting qmail-smtpd.
* Restarting qmail-smtpdssl.

Now the annoying sslserver: fatal: unable to load certificate message is no more and all works fine, Hooray! 😉

How to renew self signed QMAIL toaster and QMAIL rocks expired SSL pem certificate

Friday, September 2nd, 2011

qmail_toaster_logo-fix-qmail-rocks-expired-ssl-pem-certificate

One of the QMAIL server installs, I have installed very long time ago. I've been notified by clients, that the certificate of the mail server has expired and therefore I had to quickly renew the certificate.

This qmail installation, SSL certificates were located in /var/qmail/control under the names servercert.key and cervercert.pem

Renewing the certificates with a new self signed ones is pretty straight forward, to renew them I had to issue the following commands:

1. Generate servercert encoded key with 1024 bit encoding

debian:~# cd /var/qmail/control
debian:/var/qmail/control# openssl genrsa -des3 -out servercert.key.enc 1024
Generating RSA private key, 1024 bit long modulus
...........++++++
.........++++++
e is 65537 (0x10001)
Enter pass phrase for servercert.key.enc:
Verifying - Enter pass phrase for servercert.key.enc:

In the Enter pass phrase for servercert.key.enc I typed twice my encoded key password, any password is good, here though using a stronger one is better.

2. Generate the servercert.key file

debian:/var/qmail/control# openssl rsa -in servercert.key.enc -out servercert.key
Enter pass phrase for servercert.key.enc:
writing RSA key

3. Generate the certificate request

debian:/var/qmail/control# openssl req -new -key servercert.key -out servercert.csr
debian:/var/qmail/control# openssl rsa -in servercert.key.enc -out servercert.key
Enter pass phrase for servercert.key.enc:writing RSA key
root@soccerfame:/var/qmail/control# openssl req -new -key servercert.key -out servercert.csr
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:UK
State or Province Name (full name) [Some-State]:London
Locality Name (eg, city) []:London
Organization Name (eg, company) [Internet Widgits Pty Ltd]:My Company
Organizational Unit Name (eg, section) []:My Org
Common Name (eg, YOUR name) []:
Email Address []:admin@adminmail.com

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

In the above prompts its necessery to fill in the company name and location, as each of the prompts clearly states.

4. Sign the just generated certificate request

debian:/var/qmail/control# openssl x509 -req -days 9999 -in servercert.csr -signkey servercert.key -out servercert.crt

Notice the option -days 9999 this option instructs the newly generated self signed certificate to be valid for 9999 days which is quite a long time, the reason why the previous generated self signed certificate expired was that it was built for only 365 days

5. Fix the newly generated servercert.pem permissions debian:~# cd /var/qmail/control
debian:/var/qmail/control# chmod 640 servercert.pem
debian:/var/qmail/control# chown vpopmail:vchkpw servercert.pem
debian:/var/qmail/control# cp -f servercert.pem clientcert.pem
debian:/var/qmail/control# chown root:qmail clientcert.pem
debian:/var/qmail/control# chmod 640 clientcert.pem

Finally to load the new certificate, restart of qmail is required:

6. Restart qmail server

debian:/var/qmail/control# qmailctl restart
Restarting qmail:
* Stopping qmail-smtpd.
* Sending qmail-send SIGTERM and restarting.
* Restarting qmail-smtpd.

Test the newly installed certificate

To test the newly installed SSL certificate use the following commands:

debian:~# openssl s_client -crlf -connect localhost:465 -quiet
depth=0 /C=UK/ST=London/L=London/O=My Org/OU=My Company/emailAddress=admin@adminmail.com
verify error:num=18:self signed certificate
verify return:1
...
debian:~# openssl s_client -starttls smtp -crlf -connect localhost:25 -quiet
depth=0 /C=UK/ST=London/L=London/O=My Org/OU=My Company/emailAddress=admin@adminmail.com
verify error:num=18:self signed certificate
verify return:1
250 AUTH LOGIN PLAIN CRAM-MD5
...

If an error is returned like 32943:error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:s23_clnt.c:607: this means that SSL variable in the qmail-smtpdssl/run script is set to 0.

To solve this error, change SSL=0 to SSL=1 in /var/qmail/supervise/qmail-smtpdssl/run and do qmailctl restart

The error verify return:1 displayed is perfectly fine and it's more of a warning than an error as it just reports the certificate is self signed.

How to check if newly installed SSL certificate for IMAP and IMAPS is properly installed

Tuesday, June 28th, 2011

Did you have to regenerate your SSL certificate for your mail server’s IMAP and IMAP SSL service?
Did you have to find out if the newly installed certificates are fine after install?

Here is how:

          root@server-hosting [/usr/local ]# openssl s_client -connect imap.example.com:993
root@server-hosting [/usr/local ]# openssl s_client -connect imap.example.com:143 -starttls imap

The output returned by this two commands will be the imap and imaps configured certificates as well as extensive info concerning the installed SSL, the last chunk of info to be spit is most crucial to know if certificate is fine.
It should be something like:

...
New, TLSv1/SSLv3, Cipher is AES256-SHA
Server public key is 1024 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
Protocol : TLSv1
Cipher : AES256-SHA
Session-ID: 0B69E91022CB56D64F56CFA08405944D9C4C0069EE4097890B98F1406CF084D5
Session-ID-ctx:
Master-Key: 13745B94E0C5A0604EB7529E7409251961DFD5F4134F3A8F
Key-Arg : None
Start Time: 1309265383
Timeout : 300 (sec)
Verify return code: 18 (self signed certificate)
---
. OK CAPABILITY completed
closed