The GHOST Vulnerability (and yes, this blog is still alive :))

After Heartbleed and Poodle in 2014, it's now time for the first major security vulnerability in Linux systems in 2015 : GHOST The GHOST vulnerability is a serious weakness in the Linux glibc library which 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. You can read more about this issue here : https://community.qualys.com/blogs/laws-of-vulnerabilities/2015/01/27/the-ghost-vulnerability You can list all packages/applications depends upon vulnerable Glibc, by running the following command on your server : lsof | grep libc | awk '{print $1}' | sort | uniq As you can see, a lot of packages are using Glibc library on Linux. If you want to check your glibc version, you can run : ldd --version Now, to patch your Ubuntu/Debian server, ...

How to prevent SPAM from your own domain

Sometimes on a professionnal mailbox, you can receive SPAM from your own domain and maybe even from your own email address. If you are in this case, the first thing to do is to analyze the email header in order to see from which SMTP server the email is coming : Either the SMTP server is really your internal SMTP, which means that one of your LAN machine is probably infected, or your SMTP server is an open relay Either you will see that the email is routed by an external SMTP server, spoofing your own address, before being delivered to you. That's a good thing, in this case, you will be able to stop it. Explanations Anyone with sufficient knowledge can send an email with any address in the "From" field. It's like that since the beginning of the emails ...