Change Time Zone from Command line | CentOS | RHEL | Ubuntu | Fedora

Hello,

As you all know, It is very easy to change Time Zone using Graphical Interface but this article will help you change TimeZone Using command line.

Time Zone

I have tested these steps on CentOS / RHEL and Ubuntu, Please comment down below if doesn’t work for you.

Please follow these steps as root or with root equivalent sudo rights:

  • Check Time Zone using following command
    [root@tejas-barot-linux-ahmedabad ~]# date
  • First Remove symbolic link of current time zone
     [root@tejas-barot-linux-ahmedabad ~]# rm /etc/localtime
     
  • Let’s Change the Time Zone from Command line
    [root@tejas-barot-linux-ahmedabad ~]# ln -sf /usr/share/zoneinfo/Asia/Kolkata /etc/localtime
     

Note : You can find your time zone under /usr/share/zoneinfo/

Disable rate-limiting in rsyslog v5 | Linux | RHEL | CentOS | Ubuntu

Hello,

First of all extremely sorry for not being active as I was busy with some work, Now back to the blogging.

This article will show you how to disable rsyslog rate-limiting, But You can also use rate-limiting according to your requirement.

How to use rate limiting in rsyslog?

This article is tested with rsyslog 5.7.1 on Fedora 13. It will not work with version of rsyslog prior to 5.7.1.

In rsyslog 5.7.1 we introduced rate limiting. This is a option for the Unix Socket Input module called imuxsock. In short, this option limits the amount of messages written into logfiles by a process, if the process tries to write huge amounts of messages in a short period of time.

To Read more Visit : http://www.rsyslog.com/tag/rate-limiting/

Rsyslog
Rsyslog

If you are receiving error messages like below in /var/log/messages

imuxsock begins to drop messages from pid 5923 due to rate-limiting 

Please following below method to stop / disable rate-limiting in rsyslog in version 5.

Note: rsyslog version 7 has this disabled by default but rsyslog version 5 has this enabled.

To disable it, add following parameters to your /etc/rsyslog.conf , You need to add with root user or root equivalent user.

$SystemLogRateLimitInterval 0
$SystemLogRateLimitBurst 0

Execute following command to restart rsyslog services

service rsyslog restart

Download Fedora 22 Final CD / DVD / ISO / 32-Bit / x86_64

Hello,

Fedora 22 released few days back and now available for download, Sorry for delay in posting of download links, You can download using following Links.

Note: Fedora 22 will be using now DNF instead of YUMYUM IS DEAD !

Fedora 22 Download
Fedora 22 Download

Download Fedora 22 Workstation 64-Bit Live Image (x86_64): http://download.fedoraproject.org/pub/fedora/linux/releases/22/Workstation/x86_64/iso/Fedora-Live-Workstation-x86_64-22-3.iso

Download Fedora 22 Workstation 32-Bit Live Image (i386): http://download.fedoraproject.org/pub/fedora/linux/releases/22/Workstation/i386/iso/Fedora-Live-Workstation-i686-22-3.iso

Download Fedora 22 Server 64-Bit Installation Image (x86_64): http://download.fedoraproject.org/pub/fedora/linux/releases/22/Server/x86_64/iso/Fedora-Server-DVD-x86_64-22.iso

Download Fedora 22 Server 32-Bit Installation Image (x86_64): http://download.fedoraproject.org/pub/fedora/linux/releases/22/Server/i386/iso/Fedora-Server-DVD-i386-22.iso

Download Fedora 22 Cloud Images : https://getfedora.org/en/cloud/download/

HowTo: Install MySQL Workbench on RHEL 5.x / CentOS 5.x | x86_64

Hello

What is MySQL Workbench ?

MySQL Workbench is a unified visual tool for database architects, developers, and DBAs. MySQL Workbench provides data modeling, SQL development, and comprehensive administration tools for server configuration, user administration, backup, and much more. MySQL Workbench is available on Windows, Linux and Mac OS X.

MySQL Workbench
MySQL Workbench

Sharing article which will help you all to Install MySQL Workbench on RHEL 5.4 / CentOS 5.4 x86_64 (64-Bit).

Please follow below steps to install MySQL Workbench on RHEL 5.x / CentOS 6.x 64 Bit version.

1. You need to be root to install RPMs.

2. Download MySQL-Workbench RPM from below link,

[root@tejasbarot ~]# wget ftp://ftp.pbone.net/mirror/dev.mysql.com/pub/Downloads/MySQLGUITools/mysql-workbench-oss-5.2.17-1centos.el5.x86_64.rpm

3. Download dependencies from below link:

[root@tejasbarot ~]#  wget http://tejasbarot.com/RPMs/downloads/mysql-workbench.tar.gz
[root@tejasbarot ~]# tar zxvf mysql-workbench.tar.gz
[root@tejasbarot ~]# cd mysql-workbench
[root@tejasbarot mysql-workbench]# rpm -Uvh *.rpm

4. Now Next step to Install downloaded RPM MySQL-Workbench in step 2.

[root@tejasbarot ~]# yum -y localinstall mysql-workbench-oss-5.2.17-1centos.el5.x86_64.rpm --nogpgcheck

5. That’s it. Now Wait for dependencies to be installed and MySQL Workbench will be ready for you.

Hope this will be helpful to you all.

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Linux: The GHOST Vulnerability | RHEL | CentOS

The GHOST vulnerability is a serious weakness in the Linux glibc library. It allows attackers to remotely take complete control of the victim system without having any prior knowledge of system credentials. CVE-2015-0235 has been assigned to this issue.

 

Qualys security researchers discovered this bug and worked closely with Linux distribution vendors. And as a result of that we are releasing this advisory today as a co-ordinated effort, and patches for all distribution are available January 27, 2015.

 

What is glibc?

The GNU C Library or glibc is an implementation of the standard C library and a core part of the Linux operating system. Without this library a Linux system will not function.

 

What is the vulnerability?

During a code audit Qualys researchers discovered a buffer overflow in the __nss_hostname_digits_dots() function of glibc. This bug can be triggered both locally and remotely via all the gethostbyname*() functions. Applications have access to the DNS resolver primarily through the gethostbyname*() set of functions. These functions convert a hostname into an IP address.

 

Ghost Vulnerability
Ghost Vulnerability

 

 

What is the risk?

There is a remote code execution risk due to this vulnerability. An attacker who exploits this issue can gain complete control of the compromised system.

 

Is the risk real?

During our testing, we developed a proof-of-concept in which we send a specially created e-mail to a mail server and can get a remote shell to the Linux machine. This bypasses all existing protections (like ASLR, PIE and NX) on both 32-bit and 64-bit systems.

 

What can be done to mitigate the risk?

The best way to mitigate the risk is to apply a patch from your Linux vendor. Qualys has worked closely with Linux distribution vendors and patches are available as of today January 27, 2015.

 

Why is it called the GHOST vulnerability?

It is called as the GHOST vulnerability as it can be triggered by the GetHOST functions.

 

Is this a design flaw?

No. This is an implementation problem in the affected versions of the software.

 

What versions and operating systems are affected?

The first vulnerable version of the GNU C Library affected by this is glibc-2.2, released on November 10, 2000. We identified a number of factors that mitigate the impact of this bug. In particular, we discovered that it was fixed on May 21, 2013 (between the releases of glibc-2.17 and glibc-2.18). Unfortunately, it was not recognized as a security threat; as a result, most stable and long-term-support distributions were left exposed including Debian 7 (wheezy), Red Hat Enterprise Linux 6 & 7, CentOS 6 & 7, Ubuntu 12.04, for example.

 

Where can I download the exploit?

We want to give everyone enough time to patch. According to our data once the vulnerability has reached its half-life we will release the exploit. Half-life is the time interval measuring a reduction of a vulnerability’s occurrence by half. Over time, this metric shows how successful efforts have been to eradicate vulnerability. A shorter half-life indicates faster remediation. Half-life was originally coined by Qualys in the Laws of Vulnerability.

 

Qualys customers can detect GHOST by scanning with the Qualys Vulnerability Management (VM) cloud solution as QID 123191. This means that Qualys customers can get reports detailing their enterprise-wide exposure during their next scanning cycle, which allows them to get visibility into the impact within their organization and efficiently track the remediation progress of this serious vulnerability.

 

References:

Qualys Advisory: https://www.qualys.com/research/security-advisories/GHOST-CVE-2015-0235.txt

RedHat: https://rhn.redhat.com/errata/RHSA-2015-0090.html

Ubuntu: https://launchpad.net/ubuntu/+source/eglibc

Debian: https://security-tracker.debian.org/tracker/CVE-2015-0235

Oracle Enterprise Linux: https://oss.oracle.com/pipermail/el-errata/2015-January/004810.html

CentOS: http://lists.centos.org/pipermail/centos-announce/2015-January/020906.html

OpenSUSE: http://lists.opensuse.org/opensuse-updates/2015-01/msg00085.html

GNU C Library: http://www.gnu.org/software/libc/

Mitre: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0235

Link to Original Article : https://community.qualys.com/blogs/laws-of-vulnerabilities/2015/01/27/the-ghost-vulnerability

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SAR GUI: Export sar / sysstat reports as PDF using kSar

Hello,

If you are Linux Administrator you must know what SAR is, sar is a very useful utility for Linux Administrators to get the report of CPU Usage and You can monitor I/O, CPU Usage, Idle system state using sar utility. This article will help you to read / export sar reports in Graphical mode.

In this HowTo, I will show you how you can export sar reports as PDF / JPG / PNG using kSar tool.

ksar - PDF
ksar – PDF

In RHEL / CentOS you will find sar reports under /var/log/sa

In Ubuntu / Debian based Linux you will find sar reports under /var/log/sysstat

Perform following steps to export sar report:

1. Make Sure Java is installed on your system to open kSar Utility.

2. Download kSar Utility from below URL

http://sourceforge.net/projects/ksar/

3. Extract / Unzip Downloaded ksar-x-x-x.zip file

root@tejas-barot-linux-ahmedabad:~/Downloads# unzip kSar-5.0.6.zip

4. Give Executable permission to kSar.jar

root@tejas-barot-linux-ahmedabad:~/Downloads/kSar-5.0.6# chmod +x kSar.jar

5. Execute below command to open java file (kSar.jar):

root@tejas-barot-linux-ahmedabad:~/Downloads/kSar-5.0.6# java -jar kSar.jar

6. Now Click on Data -> Load from Text file…

7. Provide Path of sar reports path:

For RHEL: /var/log/sa/sarXX
For Debian/Ubuntu: /var/log/sysstat/sarXX

8. Select “Export to PDF / JPG / PNG” from Data  To Export sar report as PDF / JPG / PNG

Enjoy Sysstat Monitoring 🙂 Enjoy GUI Reports 🙂 Enjoy Linux 🙂 Enjoy Open Source 🙂

This is how you can export sar reports in Graphical format.

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ShellShock Bug: Check / Identify / Solve Vulnerability

Hello,

Patch your bash now Just heard that your shell / bash may be vulnerable or buggy.

This post will help you to check whether your Shell / bash of Red Hat Enterprise Linux is vulnerable / Bug infected or not.

How does this impact systems

This issue affects all products which use the Bash shell and parse values of environment variables. This issue is especially dangerous as there are many possible ways Bash can be called by an application. Quite often if an application executes another binary, Bash is invoked to accomplish this. Because of the pervasive use of the Bash shell, this issue is quite serious and should be treated as such.

All versions prior to those listed as updates for this issue are vulnerable to some degree.

See the appropriate remediation article for specifics.

The patch for CVE-2014-7169 introduces changes to how Bash evaluates environment variables. Applications which directly create Bash functions as environment variables need to be made aware of these changes. Previously, a function had to be stored in an environment variable of the same name. For example, the function “compute” would be stored in an environment variable named “compute”. With the patch for CVE-2014-7169 applied, it would need to use the name “BASH_FUNC_compute()”. As a result, there are now two pairs of parentheses in the environment string, as in “BASH_FUNC_compute()=() { }”.

Functions written in Bash itself do not need to be changed, even if they are exported with “export -f”. Bash will transparently apply the appropriate naming when exporting, and reverse the process when importing function definitions.

 

ShellShock
ShellShock

Execute following command to check whether your bash / shell is bug infected or vulnerable!

So, how do you know if your servers can be attacked? First, you need to check to see if you’re running a vulnerable version of Bash. To do that, run the following command from a Bash shell:

env x='() { :;}; echo vulnerable' bash -c "echo this is a test"

If you get the result:

vulnerable
this is a test

Bad news, your version of Bash can be hacked. If you see:

bash: warning: x: ignoring function definition attempt bash: error importing function definition for `x’ this is a test

You’re good. Well, to be more exact, you’re as protected as you can be at the moment.

OR

To test if your version of Bash is vulnerable to CVE-2014-6271, run the following command:

$ env 'x=() { :;}; echo vulnerable' 'BASH_FUNC_x()=() { :;}; echo vulnerable' bash -c "echo test"

If the output of the above command contains a line containing only the word vulnerable you are using a vulnerable version of Bash. The patch used to fix this issue ensures that no code is allowed after the end of a Bash function.

Note that different Bash versions will also print different warnings while executing the above command. The Bash versions without any fix produce the following output:

$ env 'x=() { :;}; echo vulnerable' 'BASH_FUNC_x()=() { :;}; echo vulnerable' bash -c "echo test"
vulnerable
bash: BASH_FUNC_x(): line 0: syntax error near unexpected token `)'
bash: BASH_FUNC_x(): line 0: `BASH_FUNC_x() () { :;}; echo vulnerable'
bash: error importing function definition for `BASH_FUNC_x'
test

The versions with only the original CVE-2014-6271 fix applied produce the following output:

$ env 'x=() { :;}; echo vulnerable' 'BASH_FUNC_x()=() { :;}; echo vulnerable' bash -c "echo test"
bash: warning: x: ignoring function definition attempt
bash: error importing function definition for `x'
bash: error importing function definition for `BASH_FUNC_x()'
test

Read more :- https://access.redhat.com/articles/1200223

Products Affected:

Product/Channel Fixed in package Remediation details
Red Hat Enterprise Linux 7 bash-4.2.45-5.el7_0.4 Red Hat Enterprise Linux
Red Hat Enterprise Linux 6 bash-4.1.2-15.el6_5.2 Red Hat Enterprise Linux
bash-4.1.2-15.el6_5.1.sjis.1 * Red Hat Enterprise Linux
bash-4.1.2-9.el6_2.1 * Red Hat Enterprise Linux 6.2 AUS
bash-4.1.2-15.el6_4.1 * Red Hat Enterprise Linux 6.4 EUS
Red Hat Enterprise Linux 5 bash-3.2-33.el5_11.4 Red Hat Enterprise Linux
bash-3.2-33.el5_11.1.sjis.1 * Red Hat Enterprise Linux
bash-3.2-24.el5_6.1 * Red Hat Enterprise Linux 5.6 LL
bash-3.2-32.el5_9.2 * Red Hat Enterprise Linux 5.9 EUS
Red Hat Enterprise Linux 4 bash-3.0-27.el4.2 * Red Hat Enterprise Linux 4 ELS

If you are using any other version of Linux, Check and Patch it now before its too late!!

References taken from :

https://access.redhat.com/announcements/1210053
https://access.redhat.com/security/cve/CVE-2014-6271
Resolution: https://access.redhat.com/node/1207723

Be Safe 🙂 Be Secure 🙂 Enjoy Linux 🙂 Enjoy Open Source

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