Updating Metasploit is quite easy – you just need to run msfupdate command. Later, you might have to be prepared for series of errors while invoking msfconsole. For instance, I had to switch between various commands like bundle install, gem install, apt-get install etc…to fix each error. Well, if you…

Few days ago, I wrote an article on yum commands that allows you to know the version of the package available in the repository. Today I’ll be showing how to use apt-get and aptitude commands in Ubuntu to identify the version of the package before installing. I mean, you can…

Question: I have set an ip address for eth0 interface in Ubuntu and it worked for a while. But after sometime, the IP address is automatically removed from the eth0 interface in-spite of having the entry for eth0 in /etc/network/interfaces file. How to solve this issue? Solution: It can happen…

OpenStack Horizon allows you to configure network, subnets, routers etc…It also allows users to delete network with a click of a button. To do that, you need to login to the Horizon interface and click NETWORK > Networks and click on the pull down button under Actions and select “Delete…

Question: I got an error “libpci header check failed. Disable KVM Device Assignment capability” while compiling qemu-kvm package on Ubuntu server. Please tell me how to solve this error: # ./configure warning: proceeding without pkg-config Error: libpci header check failed Disable KVM Device Assignment capability. Solution: You need to install…

For one of my project, I need to install an older version of Ubuntu (11.10 oneiric release). But apt-get failed (install) or apt-get update was no longer working and failed with an error message  “Failed to fetch” and “404 not found”.  Below are the errors: $ sudo apt-get update W:…

Question: I was stuck with an error “Error: libpci check failed.  Disable KVM Device Assignment capability” while compiling qemu-kvm package on Ubuntu machine. Below is the complete error message. [qemu-kvm] $ ./configure Error: libpci header check failed Disable KVM Device Assignment capability. How to solve this error. Solution: The error…

If you ever want to instruct YUM to install only a particular version of a package, then here’s how you can do that. Well, there can be a multiple versions of package in the yum repository and if not instructed, yum will install the default version. But sometimes you might…

If you ever wanted to try Kali Linux in OpenStack, then you have landed on the right page. In this tutorial, I’ll show how to create a Kali Linux image in qcow2 format for OpenStack Mitaka. Kali Linux is one of the most advanced penetration testing distribution developed by Offensive…

Are you stuck in extracting .7z file in Linux? Then here’s how you can install 7z extractor in CentOS, RHEL and Fedora based machines. 7z files are generally smaller in size (as it creates a file with a very high compression ratio) and supports only limited compression methods. It supports…

Question: I got an error ‘Failed to start PostgreSQL database server –  Unregistered Authentication Agent for unix-process‘ while starting PostgreSQL server on CentOS machine. The error indicates that the service failed due to unregistered authentication agent for unix process and it is reported by polkitd service. I understand that the…

Question: I was stuck with an error “Metasploit requires the bundler gem to be installed” while executing msfconsole from the Metasploit framework. The issue here is, I did tried installing bundler gem using ‘gem install bundler’, but still msfconsole script produces the same error. Here’s the snapshot of the error…

Question: I was compiling Ruby version 1.9.3 on a CentOS machine and landed up with the below error message while executing make command. EC_GROUP_new_curve_GF2m undeclared (first use in this function) The error occurred while compiling ossl_pkey_ec.c file. Here’s the snapshot of the complete error: # ./configure #make ossl_pkey_ec.c: In function…

In this tutorial, I’ll be explaining about Puppet resources, manifests, modules and classes with examples. Also, I assume that you already have Puppet master/agent nodes installed and ready for use. In order to use Puppet, you need to understand how puppet handles resources and how manifest & modules are created….

Puppet, a popularly known configuration management tool for Unix and Windows based systems that allows an administrator to easily automate repetitive and error-prone system administration tasks – which includes provisioning, installation of packages/software, configurations and management of the entire infrastructure. Puppet comes in two flavors – Puppet Enterprise and Puppet…

Before we start discussing about the Auditing system, I would like to ask few questions. How do you monitor the commands executed by the user? How do you monitor whether a file or a directory was accessed? How do you record various security related events? How do you monitor system calls,…

If you have migrated your website from HTTP to HTTPS, then you must be prepared to face few hiccups. One such issue is mixed content errors – If your website serve pages via https protocol, then all active mixed contents delivered via HTTP will be blocked by the browsers and…

Nmap is an open source network mapper that allows one to scan network of hosts, services, perform security assessment and auditing. This useful command comes with loads of options and capabilities, but you need to have expertise in using it. In this tutorial, I’ll try to introduce few command examples that can help…

If you getting an error “Sudo unable to resolve host” while executing sudo command in Ubuntu, then here’s how you can fix the issue. Below is the snapshot of the error: ubuntu@test$ sudo su – sudo: unable to resolve host (test) Solution: Check if /etc/hostname contains the correct hostname of your…