Heartbleed OpenSSL bug fix on Debian Wheezy

heartbleedFollowing the Debian Security Advisory DSA-2896-1 openssl — security update, a good practice would be to check wether your server is affected by the OpenSSL  Heartbleed security bug or not.

If you find your server affected by the bug, here are some few steps to  fix the problem on Debian Wheezy (but with slight changes you can use with other distros too).

As root:

aptitude update
aptitude upgrade libssl1.0.0
aptitude upgrade openssl

As you reboot you Apache or SSH servers, you will notice that  the bug is fixed, but the problem is still here, you private keys may be compromised, so it’s time to generate new secrets.


Let’s generate a new private key. First, let’s move to the ssl private keys directory:

cd /etc/ssl/private

Let’s issue:

openssl genrsa -des3 -out server.key 1024
openssl req -new -key server.key -out server.csr

So now we have a new private key and a csr  (certificate signing  request).

Time to strip the password from the private key:

cp server.key server.key.org
openssl rsa -in server.key.org -out server.key

And now, we self sign the certificate:

openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

Have a look at your new certificate:

openssl x509 -in server.crt -text | less

Now let’s make everything readable just by root user, remember that we stripped the password from private key:

chmod o-r server*

Finally let’s copy the new public certificate to the right directory:

cp server.crt ../certs/

Do not forget to modify, if needed, the  entry for certificate  files in Apache conf :

SSLCertificateFile /etc/ssl/certs/server.crt
SSLCertificateKeyFile /etc/ssl/private/server.key

Now, restart Apache:

service apache2 restart



For OpenSSH it’s way easier. First, we remove the old host keys:

rm /etc/ssh/ssh_host_*

Now  we reconfigure openssh-server package to generate new keys:

dpkg-reconfigure openssh-server

Finally, if dpkg-reconfigure did not, we restart SSH

service ssh restart

A mod_gearman chart














Some thoughs on mod_gearman benefits.

  • It calls back  Gearmand, so it can be fitted in a vlan behind a firewall and you do not have to open any ports towards the vlan;
  • You can have more than one worker to monitor a host or service. They share the load, so you have a round robin balancing and if one faints, the others take all the checks and execute them. So, you have an easy way to  redundancy for the workers.

In this chart I “collapsed” the gearmand daemon under the  “Monitor” box.

send_gearman dirty wrapper

This is just a skeleton. It works but no  checks on input. It’s meant to be run by a cronjob, so, really, input check? 



# Mod-Gearman Passive Check Wrapper
# (few lines) coded by Giorgio Zarrelli


$SEND_BIN –server=”$SERVER” –encryption=”$ENCRYPTION” –key=”$KEY” –host=”$HOST” –service=”$SERVICE” –message=”$COMMAND” –returncode=”$RETURN_CODE”


./send_gearman.sh “/path/to/nagios/plugins/libexec/check_users -w 1 -c 5” check-users

LDAP SSO on Linux – Used for GLPI

Note to myself:


# This configuration file allows the manual to be accessed at
# http://localhost/manual/
#Loglevel debug
KeepAlive On

Alias /glpi “/var/www/glpi”

<Directory “/var/www/glpi”>

PerlAuthenHandler Apache2::AuthenNTLM
AuthType ntlm,basic
AuthName Access
require valid-user
PerlAddVar ntdomain “DOMAIN PDO  BDO”
PerlSetVar defaultdomain DOMAIN
PerlSetVar splitdomainprefix 1
PerlSetVar ntlmdebug 0
PerlSetVar ntlmauthoritative off

# Uncomment following to force use of HTTPS in Administration Server


# PHP tuning (not working on all distribution, use php.ini instead)
AddType application/x-httpd-php .php
php_flag file_uploads on
# Some PHP tuning for deployement feature up to 8 MB
# post_max_size must be greater than upload_max_filesize
# because of HTTP headers
php_value post_max_size 9m
php_value upload_max_filesize 8m
# You may have to uncomment following on errors
#php_value max_execution_time -1
#php_value max_input_time -1

# Uncomment following to allow HTTP body request up to 4 MB
# instead default 512 KB
#LimitRequestBody 4194304


Install Apache2::AuthenNTLM Perl module. In Debian just type:

aptitude install libapache2-authenntlm-perl

Remember to enable ntlm authentication on Windows machines. Not all versions (xp does), have it enabled.