Tag Archives: cis

[Puppet] fixing mod_passenger: Cannot connect to Unix socket – Permission denied in a hardened AWS Linux 2014.09

As I’ve shared in my previous post, I was working on hardening AWS Linux 2014.09 using Puppet. I got that finished and I’ll probably improve the class in the future to make it easier to manage.

The first thing you’ll realize when you harden a system is this: it will break stuff… No, I’m not talking about the small stuffs, I’m talking about major applications that you rely on.

The first to break that I noticed was running a Puppet master with httpd + mod_passenger in AWS Linux 2014.09. It won’t work properly anymore… Ugh!

Since I was in hurry when I first discovered this, I just reverted back to the default Puppet master using Ruby webrick. Performance was really not an issue since this is only for our environment where we write/test our Puppet classes…

But when I decided to separate the CA server of our Puppet master for scalability — I can’t use the default Ruby webrick anymore. I have to allot the time and investigate if what’s the root cause of the problem

passenger error

snapshot of the error

Clearly… it has something to do with permissions. The web server (httpd) cannot access the Unix socket created by mod_passenger.


version information

Reviewing the CIS guidelines for AWS Linux 2014.09 pointed me to “3.1 Set Daemon umask” which states:

CIS 3.1

This is enforced by this Puppet class via this sysconfig configuration. CIS 3.1 guideline clearly says that “The daemon process can manually override these settings if these files need additional permission.”  — which gave me an idea to override this in the httpd level.

So… override we go…

I opened /etc/init.d/httpd in vim and added a less strict umask: umask 0022


Restarted httpd and then… FIXED! 🙂

[Puppet] Hardening AWS Linux 2014.09 based on CIS benchmark

Update [2015-07-07]: Puppet module is practically done for hardening AWS Linux 2014.09, you can check it out here: https://github.com/proletaryo/cis-puppet

It’s been almost a year since I posted here. Work is very challenging nowadays…

The latest project that I’m part of is now dealing with financial services. Yup, this means a lot of security exercises that need to be done to comply with PCI-DSS (Payment Card Industry Data Security Standards). I find these exercises challenging, a new lens that let’s you understand a lot of things and even makes you paranoid sometimes. IT Security is core – I learned a lot in this area for the past few months.

Anyway, right now I’m working with OS hardening based on the benchmark provided by Center for Internet Security. They provide guidelines on how to do this. Just download the document for your OS here: https://benchmarks.cisecurity.org/downloads/multiform/index.cfm

I’m working mostly in AWS nowadays – It’s a good thing that CIS released a benchmark for AWS Linux 2014.09 version.

We’re a Puppet shop so the first thing I did was to check if there are modules for AWS Linux. the closest one that I’ve found is for RHEL: https://github.com/arildjensen/cis-puppet

Close but not close enough… but definitely better than nothing 🙂

The beauty of OSS is you can always fork a project and Github is a wonder-tool! So fork I went… I’m already done with CIS Scored guidelines 1.x.x to 3.x.x — a few more to go. Once done, I’m hoping that I can merge this back to master if the original author will allow 🙂

If you’re interested in this project, just drop me a message here: https://github.com/proletaryo/cis-puppet