How to determine Linux guest VM virtualization technology

Posted on in Categories , , , , , , , last updated June 28, 2016

I have a cloud-based virtual machine running Ubuntu and CentOS Linux server. It may or may not be virtualized. How do I determine what kind of virtualization technology (VMWARE/ KVM/ XEN/ VirtualBox/ Container/ lxc/Hyper-V etc.) a Linux guest system running on? How do I find out the virtualization type of a CentOS 7 Linux VPS?

How to gzip and keep original file on Unix or Linux command line

Posted on in Categories , , , , , , last updated March 25, 2016

I would like to compress a log file using gzip Unix command line utility, and I would also like to keep the original file. However, when I use the gzip my-app.log command, results in modifying my log file and renaming it my-app.log.gz. How do I force the gzip command to keep original file while maintaining the original file on Linux or Unix-like system?

How To Patch and Protect Linux Glibc Getaddrinfo Stack-based Buffer Overflow Zero Day Vulnerability CVE-2015-7547 and CVE-2015-5229 [ 16/Feb/2016 ]

Posted on in Categories , , , , last updated February 17, 2016

A stack-based critical buffer overflow was found in the way the libresolv library (glibc) performed dual A/AAAA DNS queries. A remote attacker could crash or, potentially, execute code running the library on Linux. How do I patch and protect my server or workstation against the glibc getaddrinfo on Linux operating system?