Bella Bella

All articles by Bella

 

CVE-2017-5638: Apache Struts 2 Vulnerability

Apache Struts 2 is an open-source development framework for Java applications. On March 6th, 2017, a vulnerability tracked as CVE-2017-5638 in Apache Struts 2 was made public. This vulnerability could allow an attacker to perform remote code execution with malicious Content. This particular vulnerability can be exploited if the attacker sends a  request to upload...
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Configuration of HAProxy Load Balancer on CentOS

HAProxy stands for High Availability Proxy.  It is a very fast and reliable solution for high availability and load balancing. HAProxy is used as TCP/HTTP Load Balancer and for proxy Solutions. The HAProxy application will share the workload with multiple servers. Steps for Installation and Configuring  HAProxy =========== Step 1: Before proceeding with the installation...
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Squid proxy installation in windows server

Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Squid has a variety of uses and advantages such as speeding up web browsing for the end user, reduces bandwidth and improves response times by caching and reusing frequently-requested web pages. It also can work as web filtering and can control...
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Deploying Openstack using Packstack

OpenStack is a set of software tools for building and managing cloud computing platforms for public and private clouds. Mostly deployed as an infrastructure-as-a-service (IaaS). Deploy virtual machines and other instances that handle different tasks for managing a cloud environment on the fly. It makes horizontal scaling easy, which means that tasks that benefit from...
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How to Fix Dirty Cow Vulnerability – CVE-2016-5195

A serious vulnerability named Dirty COW has been discovered recently which has put the Linux kernel under risk. It is said that this vulnerability was noticed nine years ago (since version 2.6.22 in 2007) and remained unnoticed throughout this time. A researcher named Phil Oester was the man behind the detection of this serious threat....
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SmartHost :- Forwarding Mails Through Postfix Server (From Exim)

A “Smart Host” (also known as a relay host) is a type of mail relay server which allows an SMTP server to route e-mail to an intermediate mail server rather than directly to the recipient’s server. This improves the performance of your server and the reliability of your e-mail delivery. Exim Server (Forwarding Server) This...
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Pluggable Authentication Module (PAM)

Pluggable Authentication Module (PAM) handle the authentication tasks of applications/services on the Linux system. In other words, it allows us to configure how applications use authentication to verify the identity of a user. In this article, we are mainly dealing with the configuration file format. The PAM configuration files are located under the directory /etc/pam.d/...
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Monitor Real Time Resource Usage in CloudLinux :: lvetop

CloudLinux is one of the widely used Operating System nowadays due to the high-level stability and advanced server security it provides, which makes it the first preference for hosting providers, especially in a shared hosting environment. LVE (Lightweight Virtual Environment) is a kernel-level technology developed by the CloudLinux team. It is lightweight and transparent. The...
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Network File System ( NFS ) on CentOS 6

The Network File System (NFS) was originally developed by SUN Micro-systems that allows communications between Linux/Unix systems. It allows you to mount your local file systems over a network and remote hosts or clients to interact with them as they are mounted locally on the same system. Benefits >> Central Data Management. >> Allows local...
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DROWN Attack – SSLv2 Vulnerablity

Security researchers identified a new OpenSSL vulnerability, called DROWN( Decrypting RSA with Obsolete and Weakened Encryption ) on March 2016. This attack was focused on servers that use the more secure TLS protocol, which also supports the obsolete SSLv2.This vulnerability allows an attacker to decrypt the highly secured TLS encrypted communication if the server houses...
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Kibana :: Installation and Setup

Kibana is an open-source data visualization plugin for Elasticsearch. It provides visualization capabilities on top of the content indexed on an Elasticsearch cluster. Users can create bar, line and scatter plots, or pie charts and maps on top of large volumes of data. You can set up Kibana and start exploring your Elasticsearch indices in...
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DISTRIBUTED DENIAL-OF-SERVICE (DDOS) ATTACKS

DDoS has emerged as a choice of weapon for hackers. DDoS attackers not only use it to target individual websites and servers of the network, but also subdue the network itself. The growing dependency and usage of the Internet, makes the impact of successful DDoS attacks more challenging for service providers and other enterprises, costing...
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Zend OpCache

The Zend OpCache provides faster PHP execution through opcode caching and optimization. It improves PHP performance by storing precompiled script bytecode in the shared memory. Installing Zend OPCache on PHP 5.3 or 5.4 1. Login to SSH on your server 2. Type the following commands: #cd /usr/local/src #wget http://pecl.php.net/get/ZendOpcache # to get the latest (master)...
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Icinga2 for CentOS7

Icinga is a fork of Nagios monitoring system. There are lots of changes and upgrades compared to Nagios, especially in version 2. The main visible difference is UI which is built on ext js. Other significant differences are in hosts and services definitions. Icinga2 designed to monitor large complex environments. Pre-requisites We need to make...
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External Authentication Techniques Available With cPanel

The Manage External Authentications interface in WHM allows you to manage the OpenID Connect-compliant identity providers that your server’s users can use to log in to cPanel, WHM, or Webmail. Today let see the common external authentication techniques available with cPanel and how to enable/disable these features : 1] External Authentication Via cPanelID -> Steps...
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Configuring cPHulk via WHM & command line

Now-a-days Brute force attacks to servers/websites are frequent. Brute force attack is generally a password guessing technique. It is a type of attack in which trying every possible combination of characters or data in order to find the decrypted message. A brute force guarantees finding the key – it’s trying every possible combination and does...
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​Installation and configuration of ‘Pyxsoft Antimalware’ in cPanel servers

Pyxsoft antimalware Plugin for cPanel/WHM protects your server from attacker scripts such as c99shell, r57shell, ANIShell, and hundreds more. It is a real-time Anti Malware for cPanel/WHM. Attackers can take control of your servers or can damage your customer’s data by uploading one of these scripts. Pyxsoft antimalware plugin works to protects your server in...
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Multiple SSL installation on single IP in cPanel

As we are aware, usually installing SSL Certificate requires Dedicated IP . The cost of this address is typically being passed down to the end user. Also the IPv4 address will be filled completely if every domain require a dedicated IP. So administrators decided to use multiple SSL installation on a single IP. Thus SNI...
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Adding additional SMTP listenerports

By default Postfix run on port 25 and 587(TLS). However some ISPs block port 25. In that case you can configure the postfix mail server to listen on additional ports too, for example port 26 or some random 5125. This configuration is done in the master.cf configuration file. Edit it in your editor of choice....
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Adminer

Adminer is a fully featured database management tool written in PHP. Adminer is an alternative to phpMyAdmin where we can manage content in MySQL, SQLite, Oracle, PostgreSQL databases effectively. Adminer Features > Basic functions : Add/remove/modify the databases and tables > Modify database objects (views, triggers, procedures, user permissions, variables, processes etc.) > Execute SQL...
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URL Monitoring With Nagios

Capabilities Nagios provides complete URL monitoring of HTTP and HTTPS servers and protocols as well as full URL transaction monitoring. Benefits Implementing effective URL monitoring with Nagios offers the following benefits: >> Increased server, services, and application availability >> Fast detection of network outages and protocol failures >> Monitor user experience when accessing URLs >>...
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Outgoing mail issue in Qmail using configured SMTP routes

If you are facing issue with outgoing mail service in Linux-Qmail server, where all the outgoing emails OR emails to any specific domain are getting stuck in the remote queue, have a try with the below solution . Issue : Outgoing mails getting queued in remote queue with below error in the server mail log...
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cPanel’s Site Software Addon Enables WordPress Auto Updates

cPanel’s Site Software disables WordPress auto updates option. We can easily enable this option, for that we need to modify the following files and note that these files were only changed on WordPress sites that were installed using cPanel’s Site Software addon. Ensure to take a backup of these files before making any changes. =>...
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Tips to Speed up WordPress

One of the main issues with hosting a WordPress website is that often it takes more than desirable time to load the home page. Below, a few tips and tricks are being discussed to improve the performance of a WordPress website. How to Speed up a WordPress website? ————————————- Fixing the page load speed of...
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Plesk update error/auto-installer error

If you are getting the below error while updating the Plesk versions or installing the microupdates , have a try with the mentioned solution : —- ERROR: Unable to download the MD5 sum for the new Parallels Installer binary. Not all packages were installed. Please, contact product technical support. —- Solution : —– Remove cache...
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FTP connectivity problem

If you are getting following error while directory listing, follow the solution provided below : ———- ftp> ls 227 Entering Passive Mode (108,61,169,245,167,161). ftp: connect: No route to host ———- Solution : 1. Edit /etc/sysconfig/iptables-config and add this line: IPTABLES_MODULES=”ip_conntrack_ftp” 2. Save it and restart iptables. That’s because passive mode use non standard ports to...
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Forcefully refreshing disk space usage directly from cPanel

If user disk space usage is reflected incorrectly in cPanel, there is a way to force refresh the disk quota of cpanel directly from cPanel. We will be able to remedy this by refreshing the cPanel cache for this user. This can be done by removing the /home/username/.cpanel/datastore directory, which will be recreated upon the...
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Compiling and installing new kernel in Redhat Linux

In our example, the current kernel version is 2.6.32.71. Lets now upgrade the kernel to higher version 3.2 1: Installing Kernel  Dependencies Installing or Compiling Kernel requires following various required packages and up-to-date system packages. Latest GCCversion Latest Ncursesdevelopment version System packages up-to-date #  yum install gcc ncurses ncurses-devel # yum update...
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Process Status : PS

A process is a single program running in its own virtual address space. Using this definition, everything running under Linux is a process. The process is a running instance of a program. Linux is a multitasking operating system, which means that more than one process can be active at once. PS can show you the...
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SSLv3 POODLE vulnerability on your server and the fixes

The SSLv3 Poodle vulnerability which was released on October 14th 2014, is an attack on the SSL 3.0 protocol and it is completely protocol based vulnerability. POODLE stands for “Padding Oracle On Downgraded Legacy Encryption”. The padding attack happens when a plain text is converted to ciphertext. The plain text message often has to be...
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CalDAV and CardDAV in cPanel 11.50

As we are aware, cPanel has introduced the latest stable version cPanel 11.50. Many new features are implemented in the latest version, which includes but are not limited to :. Support for CentOS 7 on fresh installations Synchronized Calendar & Contacts Greylisting: Protect your server against spam, Greylisting defers email received from new, unknown triplets...
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CentOS Web panel

CentOS has introduced a free Web Hosting control panel (CWP: Centos Web Panel) which is designed for easy management of servers including both Dedicated & VPS without the help of ssh console. During the installation procedure, CWP installs full LAMP stack (Apache, PHP, phpMyAdmin, webmail, mail server etc.) on your server. List of softwares installed...
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The extra second in June 30, 2015 – The Leap Second !

The International Earth Rotation & Reference Systems Service (IERS) has mentioned that an extra second is to be added to Coordinated Universal Time (UTC) at 23:59:59 on 30 June 2015 and this is to make sure the alignment of astronomical and atomic time. Coordinated Universal Time, UTC is one of the basic time conventions used...
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VENOM – QEMU vulnerability – CVE-2015-3456

VENOM vulnerability also known as QEMU exploit is the most recent vulnerability reported on May 13, 2015 and it is discovered by Jason Geffner while performing a security review of virtual machine hypervisors. VENOM stands for “Virtualized Environment Neglected Operations Manipulation”. This venom exploits QEMU, an open source machine emulator. The venom CVE-2015-3456 vulnerability resides...
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Unable to fork: Cannot allocate memory

Issue : Receiving the below error while login to a container from OpenVZ node : #vzctl enter 10524 Unable to fork: Cannot allocate memory where ‘10524’ is the id of the container you are trying to login to....
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Load Balancing via Round Robin DNS

Round Robin is a balancing mechanism used by the DNS servers which are usually used for sharing the network load and managing the load of geographically distributed Web servers. The DNS server that uses the round-robin mechanism will provide alternates for each client request. Concept:- Suppose, you have a domain name and three identical home pages...
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Switching PHP versions : An overview

PHP: Hypertext Preprocessor has been involving in all of its dynamics in the recent years. In recent times it has involved included and engulfed many of the recent development and api that has been introduced to the computer world especially web developing. Switching to higher version of PHP is always good but before proceeding the...
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Glibc – GHOST vulnerability – CVE-2015-0235 and the Fix

In Linux servers, more than 60 binaries and major services such as SSH, Named, Bash etcrely on the glibc libraries. A heap-based buffer overflow was found in __nss_hostname_digits_dots() and an attacker could use this flaw to execute arbitrary code with the privilege of the users running the application using the function gethostbyname()   Check if...
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ConfigServer Mail Queue on WHM/Cpanel Server

The Config Server Mail Queue is an addon feature available with cPanel/WHM which provides with a full-featured interface to the cPanel exim email queues from within WHM. The add-on feature provides with an interface to the cPanel user accounts email configuration without having to log in to their accounts. It is domain-based rather than account-based....
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CentOS-7 : Commands and Configuration files

CentOS-7 is now powered by version 3.10.0 of the Linux kernel, with advanced support for Linux Containers and XFS (is a high-performance 64-bit journaling file system) as the default file system. It’s also the first version of CentOS to include the systemd management engine, the firewalld dynamic firewall system, and the GRUB2 boot loader. CentOS...
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Data recovery using Scalpel and Foremost

Data recovery is the process of salvaging and handling the data through the data from damaged, failed, corrupted, or inaccessible secondary storage media when it cannot be accessed normally.  The data is recoverable because the information is not immediately removed from the disk. Nowadays many tools are available for recovering lost data. Two of the...
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Advantages of using lighttpd over Apache in VPS or low memory servers

Lighttpd is an open-source web server which is more optimized for speed-critical environments than common products. It is a high quality lightweight web server which is well suited for hosting dynamic content websites. It supports CGI, FastCGI, SCGI and HTTP protocols. Lighttpd is a secure, light, fast and very flexible web server which is designed...
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Configure Amazon backup on WHM

Amazon Simple Storage Service (Amazon S3), provides developers and IT teams with secure, durable, highly-scalable object storage. Amazon S3 is easy to use, with a simple web services interface to store and retrieve any amount of data from anywhere on the web. This article is explain about of how to take cPanel backup to amazon...
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Vesta Control Panel

Vesta control panel is a free and open source control panel in Linux. Using the Vesta control panel administrator can manage the website in his VPS and which support different flavors of Linux, supporting operating systems are RHEL 5 & 6, CentOS 5 & 6, Debian 7, Ubuntu 12.04/12.10/13.04/13.10/14.04.  The last version of Vestacp released...
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Install Wine 1.7.35 in Ubuntu/Debian/Linux Mint

Wine makes it possible to run Windows programs alongside any Unix-like operating system, particularly Linux. Wine is an implementation of the Windows Application Programming Interface (API) library, acting as a bridge between the Windows program and Linux. When a Windows program tries to perform a function, Wine will translate that program’s instruction and make it...
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PHPMyAdmin error – Access Denied Unable to establish a PHP session

On accessing PHPMyAdmin via cpanel, we will be getting an error as given below if the ownership/permission of the tmp folder for the particular cpanel user is wrong. “Access Denied Unable to establish a PHP session. If you believe that this is in error or inadvertent, contact your system administrator and ask them to review...
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AMANDA Network Backup

The Advanced Maryland Automatic Network Disk Archiver (AMANDA), is a backup solution that allows the IT administrator to set up a single master backup server to back up multiple hosts over network to tape drives/changers or disks or optical media. Amanda can back up a large number of servers and workstations running multiple versions of...
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Cage File System :: An Overview

Cage File System is a virtualized file system with a set of tools to contain each user in its own ‘cage’. Each customer will have its own fully functional CageFS, with all the system files, tools, etc. The cagefsctl command provides us many options such as to initialize, enable, mount, unmount, assigning cagefs to users(enabling...
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A practical guide Linux Socket Monitor

LSM is a network socket monitor; it is designed to track changes to Network sockets and Unix domain sockets, effectively a port monitor. It does this by a rather simple differential based comparison of current and new server sockets (Server Ports). A simple and configurable alerting system sends alerts whenever new ports activate. LSM will...
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Ping a Specific Port of a Remote Host

Ping is a networking utility used to test the reachability and round-trip time (RTT) delay of a remote host over Internet Protocol (IP). The ping utility does so by sending out a series of Internet Control Message Protocol (ICMP) echo request packets to a remote host and waiting for corresponding ICMP response packets from the...
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