Click here to close now.



Welcome!

Linux Containers Authors: Liz McMillan, Pat Romanski, Elizabeth White, Stefan Bernbo, John Esposito

Related Topics: Linux Containers, Cloud Security

Linux Containers: Blog Feed Post

Linux: Secure as a Brick

Best practices I’ve learned over the years

People who are familiar with me know that there are two things I’m not forgiving about. The first is backups, the second is security.

If backups interest you, perhaps we can discuss it some other time. This time we’re going to discuss security.

I’m going to outline in the following article some of the best practices I’ve learned along the years and help you “almost brick up, but not just yet” or “harden” your Linux server.

While reading this article, however, I suggest also reading this article as well. As we both try to tackle the same issues. I believe both articles eventually represent the same views in a different guise.

All of the ideas I’m coming up with are already implemented in shk. I suggest downloading shk, reviewing the code and using it.

Security
Do you know what is secure? – a brick.

Yes, but a brick is not functional.

When I’m trying to build a secure system, I’m using the same concepts as if I’d like to secure my house.

Yes, a house is functional.

Where Is Your Front Door?
Is the front door of your house in a conventional place? – if it is it does make it easier not only for you, but also for everybody else to enter.

Imagine the door to your house would be placed 30 meters away from the house and you’d have to remove leaves and branches over a floor door, unlock it, open it, crawl 30 meters to your house, open  and unlock the house’s main door, and only then you’ll be at home.

I bet such an entrance would surprise any potential burglar.

So what’s your door for accessing your machine?

Yes, it’s usually SSH. If it’s telnet, rsh, or any other unencrypted protocol, you live in the 1970s, please update yourself, together with your haircut.

SSH on port 22 would usually get knocked quite a lot, be it bots, or kiddies, trying to see what’s in.

Don’t believe me? – run:

 # lastb 

It’ll list all the incorrect login attempts which would usually be via SSH attempts.

How do we dig the trench away from the house and install the neat floor door? – simply move SSH to a different port. It’ll fend off most of the scanning attempts.

Port knocking can add some extra security here, but I believe that port knocking also requires you to walk around with a crowbar on a daily basis – as port knocking more or less means you keep the floor door jammed – and only the correct crowbar would open it.

Since I’m not Gordon Freeman – I’m not wandering around with a crowbar and do not use port knocking.

Who Has the Key?
With SSH moved to a different port, you should ask yourself if your door is really secure.

Is your root password strong? Honestly?

And other users on the system? Do they have a secure password? Does it matter?

After you’ve reset the root password to something which is really strong, it’s time to enforce SSH to allow only the root user.

This more or less means that even if you gave your neighbor the key to your house – in order to feed the cat – she wouldn’t be able to do it. Yes, your cat might get a bit hungry, but your house will stay in tact and the and cats usually tent to find a solution when it comes to food…

And the Windows?
You’ve just installed a super-secure door, but what about your windows? Have you left any of these unbarred? Redundant?

A redundant window might be a NFS service which runs for no reason at all on your server.

On the other hand, an unbarred window might be a HTTP service which is supposed to be exposed only internally.

It is highly recommended to instantly remove services and packages you don’t use and brick these windows up.

You can use:

 # netstat -pan | grep “\bLISTEN\b” 

This will list the services that are waiting for connections.

Install bars on the unbarred windows, in other words – use a firewall. If your HTTP service is supposed to be used only internally – seal it with a firewall.

Generally speaking, it should be easy for you – the SysAdmin – to easily know which ports of a system should be exposed externally. The rest of the ports you should lock down.

And When Someone Got In?
If someone got into your house, even if it’s dark – he can always use a headlamp and pick up whatever he wants to. If someone hacked into your system and got regular user privileges – usually it’ll be super easy for him to gain root access.

Hence, it doesn’t matter if you login as a regular user and than ‘su -’ or ‘sudo’ to root, it’s all the same. I prefer to just login as root and no other user. It’ll also make you treat things more seriously.

I also don’t bother to remove useful utilities for day-to-day use. I want my systems to be comfortable for me to maintain. I can’t be bothered if comfortability for me means comfortability also for potential attackers. Once they got in they’ll be as comfortable whether there is a sofa in the living room or not.

And I do want the sofa in the living room.

Bring It On!
Lock your house – then let your friends hack in.

Security audits are invaluable and should be carried out quite often. Whether by automatic tools such as Monitis or by colleagues.

Monitis Monitoring Platform

If you never try to hack in – you’ll never know how hard it is for an attacker.

When a system is properly secure – it’s hard also for you to hack in. And if it’s hard for you – an attacker would usually find it at least twice as hard, even if he is experienced.. A random attacker has much less information and knowledge as to how your system is built, comparing to you.

A Crack in a Wall
Cracks in a wall can cause the whole wall to collapse, rendering your defenses useless.

A crack in the wall can come in the shape of an outdated apache server – with a recent exploit on the wild.

Another crack in the wall could be a 3rd party piece of software you can’t audit – but must expose to the outside world. Be extra cautious with these.

Sending your root password in plain text emails is highly discouraged just as well for the same reasons.

Aftermath
Got hacked?

In real life we will not burn a house that was broken into, but if you did get hacked, assess the situation. In 99% of the cases I would suggest to reinstall the machine freshly. The reason for that is that an attacker could install numerous back doors and it might take you ages to find them.

Reinstalling is a big headache if your system is not setup properly, or if you don’t have proper backups.

But do trust me – in the long run, it is highly recommended to avoid future problems.

Unbreakable?
If you have a house, people can break into it. Period.

Do trust me though, that usually, if you’ve decided to place your door in a non-trivial place, the casual attacker/burglar will just decide to bother the next server/house.

Carry out the rest of the defenses that are outlined here and you are more than good to go.

It sounds very simplistic, I know. But if there’s something ironic I’ve seen in life is an uber-extra-comprehensive  firewall setup on an extremely secure system, and a login of admin/123456 that caused everything to collapse.

shk
shk
will help you do the tasks I’ve outlined through this article. Tasks such as:

  • Firewall configuration
  • Altering SSH configuration
  • Setting sysctl parameters
  • Disabling services
  • Removing packages

shk is written purely in Bash and is supposed to work on most Redhat and Debian systems.

The default configuration is a bit forgiving, feel free to play with it as much as you need.

shk is free – I’d be more than happy to receive contributions and suggestions for improvement.

Read the original blog entry...

More Stories By Hovhannes Avoyan

Hovhannes Avoyan is the CEO of PicsArt, Inc.,

@ThingsExpo Stories
Cloud Expo, Inc. has announced today that Andi Mann returns to 'DevOps at Cloud Expo 2016' as Conference Chair The @DevOpsSummit at Cloud Expo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited t...
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
IoT is rapidly changing the way enterprises are using data to improve business decision-making. In order to derive business value, organizations must unlock insights from the data gathered and then act on these. In their session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, and Peter Shashkin, Head of Development Department at EastBanc Technologies, discussed how one organization leveraged IoT, cloud technology and data analysis to improve customer experiences and effi...
Internet of @ThingsExpo has announced today that Chris Matthieu has been named tech chair of Internet of @ThingsExpo 2016 Silicon Valley. The 6thInternet of @ThingsExpo will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Presidio has received the 2015 EMC Partner Services Quality Award from EMC Corporation for achieving outstanding service excellence and customer satisfaction as measured by the EMC Partner Services Quality (PSQ) program. Presidio was also honored as the 2015 EMC Americas Marketing Excellence Partner of the Year and 2015 Mid-Market East Partner of the Year. The EMC PSQ program is a project-specific survey program designed for partners with Service Partner designations to solicit customer feedbac...
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, provided an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profession...
"There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...
Ask someone to architect an Internet of Things (IoT) solution and you are guaranteed to see a reference to the cloud. This would lead you to believe that IoT requires the cloud to exist. However, there are many IoT use cases where the cloud is not feasible or desirable. In his session at @ThingsExpo, Dave McCarthy, Director of Products at Bsquare Corporation, will discuss the strategies that exist to extend intelligence directly to IoT devices and sensors, freeing them from the constraints of ...
Connected devices and the industrial internet are growing exponentially every year with Cisco expecting 50 billion devices to be in operation by 2020. In this period of growth, location-based insights are becoming invaluable to many businesses as they adopt new connected technologies. Knowing when and where these devices connect from is critical for a number of scenarios in supply chain management, disaster management, emergency response, M2M, location marketing and more. In his session at @Th...
Extracting business value from Internet of Things (IoT) data doesn’t happen overnight. There are several requirements that must be satisfied, including IoT device enablement, data analysis, real-time detection of complex events and automated orchestration of actions. Unfortunately, too many companies fall short in achieving their business goals by implementing incomplete solutions or not focusing on tangible use cases. In his general session at @ThingsExpo, Dave McCarthy, Director of Products...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform and how we integrate our thinking to solve complicated problems. In his session at 19th Cloud Expo, Craig Sproule, CEO of Metavine, will demonstrate how to move beyond today's coding paradigm ...
There are several IoTs: the Industrial Internet, Consumer Wearables, Wearables and Healthcare, Supply Chains, and the movement toward Smart Grids, Cities, Regions, and Nations. There are competing communications standards every step of the way, a bewildering array of sensors and devices, and an entire world of competing data analytics platforms. To some this appears to be chaos. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Bradley Holt, Developer Advocate a...
Apixio Inc. has raised $19.3 million in Series D venture capital funding led by SSM Partners with participation from First Analysis, Bain Capital Ventures and Apixio’s largest angel investor. Apixio will dedicate the proceeds toward advancing and scaling products powered by its cognitive computing platform, further enabling insights for optimal patient care. The Series D funding comes as Apixio experiences strong momentum and increasing demand for its HCC Profiler solution, which mines unstruc...
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...
In addition to all the benefits, IoT is also bringing new kind of customer experience challenges - cars that unlock themselves, thermostats turning houses into saunas and baby video monitors broadcasting over the internet. This list can only increase because while IoT services should be intuitive and simple to use, the delivery ecosystem is a myriad of potential problems as IoT explodes complexity. So finding a performance issue is like finding the proverbial needle in the haystack.
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
The IoT is changing the way enterprises conduct business. In his session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, discussed how businesses can gain an edge over competitors by empowering consumers to take control through IoT. He cited examples such as a Washington, D.C.-based sports club that leveraged IoT and the cloud to develop a comprehensive booking system. He also highlighted how IoT can revitalize and restore outdated business models, making them profitable ...
IoT offers a value of almost $4 trillion to the manufacturing industry through platforms that can improve margins, optimize operations & drive high performance work teams. By using IoT technologies as a foundation, manufacturing customers are integrating worker safety with manufacturing systems, driving deep collaboration and utilizing analytics to exponentially increased per-unit margins. However, as Benoit Lheureux, the VP for Research at Gartner points out, “IoT project implementers often ...