July 22, 2015

SSLv3 POODLE vulnerability

Filed under: General Topics,Miscellaneous,Server Security — Bella @ 11:13 pm

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 expanded to be compatible with the underlying cryptographic structure and the leakage of data mainly occur during the decryption of the cipher text.

The SSLv3 poodle vulnerability allows a man-in-the-middle attacker to decrypt ciphertext using a padding oracle attack. (more…)

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July 16, 2015

CalDAV and CardDAV in cPanel 11.50

Filed under: General Topics,Miscellaneous — Bella @ 11:25 pm

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
  • Passive OS fingerprinting (p0f) : Improved the GeoIP identifier and added operating system and other information to email notifications. This information helps you quickly identify users that trigger events.
  • Changes to new cPanel user system IDs : Changed the possible numbers for new cPanel accounts’ User IDs (UIDs) and Group IDs (GIDs).

In this article, let’s see more about synchronizing Calendar & Contacts using CalDAV and CardDAV. (more…)

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June 24, 2015

CentOS Web panel

Filed under: General Topics,Linux Basics,Technical Articles — Bella @ 9:47 pm

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 installation procedure, CWP installs full LAMP stack (apache, php, phpmyadmin, webmail, mailserver etc.) on your server.

List of softwares installed and configured during CWP installation are as below:

Apache Web Server
PHP 5.4
MySQL + phpMyAdmin
Postfix + Dovecot + roundcube webmail
CSF Firewall
Backups; AutoFixer for server configuration
Varnish Cache server
suPHP & suExec
Mod Security + OWASP rules
Monitor services eg. top, apache stats, mysql etc.

In this article, let’s have a check with the server requirements and features of CWP in Linux servers. (more…)

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June 23, 2015

The extra second in June 30, 2015 – The Leap Second !

Filed under: General Topics,Server Tweaking — Bella @ 12:10 am

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 by most of the world’s local time zones. This UTC time convention has been derived from a bunch of atomic clocks that are distributed across several countries globally.

The rotation of our earth is not so constant and it changes a bit over time and in-turn it decreases the mean rotation speed slowly. This is the exact cause behind leap seconds that gets added up to the UTC time scale, as they adjust the process of the UTC time itself to scale the real earth rotation.

This 1 second adjustment have hardly affected the normal human lives till now. But high performance timekeeping is most important for scientific and economic computing because even a second interruption may become stunningly important in these technologies. This scenario was last observed in 2012 when a second was added to the world time. Websites like Foursquare, Reddit, LinkedIn suffered glitches as the extra second got added because their system clocks were unable to figure out the sudden change.

In fact, on June 30, 2015 when the clock stuck 23:59:60, this will cause problems to many scientific and economic computing systems which are not programmed for this additional time. As conventional computing systems depend on precise time by using the Network Time Protocol (NTP) to be in match with the world’s atomic clocks, issues are expected, as many systems are not programmed for this extra leap second.

The International Earth Rotation and Reference System Service (IERS) in Paris, France observes the time between earth’s rotation and the atomic time. When the difference between the two approaches 0.9 seconds, they order a leap second to be added worldwide.

The workaround for this in our Linux machines is to reboot the server before the leap second period and then execute “date -s now” command in the server so as to update the leap second in the server.

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May 22, 2015

VENOM – QEMU vulnerability – CVE-2015-3456

Filed under: Miscellaneous,Server Security — Bella @ 1:23 am

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 in the virtual floppy drive code (FDC) used by the virtualization platforms. If it gets exploited, it allows an attacker to gain full control of the operating system hosting them and as well as on the other guest VMs running on the same host machine.

This is an Image

Failure to mitigate this issue, this exploited virtual machine escape could open access to the host system and all other VMs running on that host, potentially giving elevated access to the host’s local network and adjacent systems running on the network.

Generally, to eliminate the possibility of exploitation, proceed with the following.

To install the updates using the yum package manager, execute the command given below.

yum update

To update the QEMU package and its dependencies alone, execute the command given below.

yum update qemu-kvm

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