Click here to close now.

Welcome!

Linux Authors: AppDynamics Blog, Carmen Gonzalez, Roger Strukhoff, Pat Romanski, Hovhannes Avoyan

Related Topics: Linux

Linux: Article

Securing a Tightly Integrated OS

Protect your system with a layered approach

As the state of the art in operating systems (OS) continues to advance, an unnerving trend has emerged: vulnerabilities in tightly integrated operating systems. How do you address this? With an effective combination of educated staff, proper procedures, and technology.

Rather than being a collection of separate utilities and daemons, the modern OS is moving toward a highly integrated system with numerous dependencies. As a result, the core of the OS is more easily exposed to a broader range of vulnerabilities. While Linux still largely a collection of separate components, Microsoft Windows is at the forefront of this design principle and, in fact, is moving to an even more tightly integrated system. The risks can become significant. Whenever a vulnerability is found in one of the core components of a tightly integrated OS, interdependent components are vulnerable as a result. Developing an appropriate approach to protecting systems with tightly integrated OSs is the key to maintaining a secure and safe network environment.

The rationale for a tightly integrated operating system is sound - reduced development costs and effort, a reduction in portability issues, and fewer components to break. The flip side is unprecedented exposure to vulnerabilities. In the past, when a single system component had a vulnerability the impact was isolated to that single component. However, due to the dependencies introduced by extensive integration, that one component may now impact multiple applications. It is this chain of dependencies that presents enormous risk.

A Practical Approach to Isolating the Exposures

A number of approaches exist for isolating - or at least reducing - your exposure in cases such as these. For the purposes of this article, the assumption is that it is impossible to catch every security flaw during development and that organizations will need to take measures to protect themselves until patches or upgrades are available that solve the security flaw.

The simplest approach to dealing with exploits aimed at integrated OSs is to turn off any services not required or restrict access to those services via network firewalls or network intrusion prevention systems (IPSs). Turning off a service entirely is rarely a practical option for Web servers or file servers. In the specific case of a Web server, doing so would certainly solve the problem, but then you wouldn't have a Web server!

A layered approach consisting of the following primary components is the most practical solution:

  1. Education of your network and system administrators
  2. A baseline of the current state of your network
  3. Proper configuration of the host operating system, including current patches and service packs
  4. Proper configuration of the network service being hosted
  5. A generic network firewall to allow only specific traffic in and out
  6. An IPS to cover the bases left open by the network firewall
  7. An on-board firewall for each device (IPtables in Linux, TCP Filters in Windows)
  8. In the case of a Linux system, a chrooted environment for each available network service, and optionally physical separation from the internal network
Having an educated and security-conscious staff is the most important of these options. The ability to recognize, understand, and correct a potential security exposure or configuration error is much more valuable than any technology solution. Your staff is truly the first line of defense.

Knowledge is power! Knowing your current exposures and configuration issues should be on your short list, regardless of how far into this process you may go. Rectifying the issues found should be the immediate next step - directly followed by another baseline to once again ascertain any new issues. Automated vulnerability management tools can help make this process straightforward and manageable.

Current shipping distributions of Linux as well as current shipping versions of Windows still contain many services that are not useful or appropriate for a device that will host publicly accessible network services. You should identify and disable these services before the device is ever connected to any network. Linux is able to fully function with far fewer resources than Windows, and you should take advantage of this. If the first step (i.e., a well-educated staff) was successful, your administrators will be able to identify which services to safely disable.

The network service itself, for example a Web server, should also be properly configured. No prepackaged examples or documents should be present anywhere within the document root, nor should any of this data be accessible by anyone over the network. For example, many exploits exist that rely upon these stock examples being installed in a default installation of the Microsoft IIS Web server.

Every network that is to be interconnected with any other network should have a firewall at the gateway. The firewall should be configured to only allow specific traffic both into and out of the network. Nearly every firewall controls inbound traffic, but few are configured to also control outbound traffic. For example, should an internal system ever be infected with a worm (as has happened both with Linux and Windows), the outbound controls will hopefully limit the impact and propagation of the worm.

An intrusion prevention system (IPS) is a great tool to fill in the cracks that a firewall leaves open. As most firewalls do not normally perform any type of content inspection (or very limited if they do), the allowed traffic is by no means assured to be free of malicious content or exploits. This is where an IPS really shines - the ability to inspect all traffic for attacks. Most IPS products also allow the traffic to be blocked, hence the prevention in intrusion prevention system. The value of an IPS is often discounted or misunderstood, yet for those in the know, an IPS represents a 24/7 partner that never stops preventing the malicious traffic from entering your network.

An on-board firewall is a critical component that will shield your organization from the inevitable configuration error. By restricting which types of network traffic may be passed into and out of each endpoint, you greatly reduce your exposure. Windows and Linux have this capability. Most Linux distributions use this out of the box; however, Windows must be configured after the fact to leverage this capability, although Service Pack 2 for Windows XP will change that.

Chrooted environments are an extremely effective means to isolate processes on a Linux system. Linux has native support for chrooted environments and most distributions ship with tools out of the box that will allow you to do this for nearly any network service (or any process for that matter!). Unfortunately, Windows has no good way to implement a chrooted environment. A somewhat feasible option for Windows includes running VMware, but the resources required are often too much, making this impractical. The primary benefit of a chrooted environment is the logical separation: if a process or application is exploited, the damage is limited to the chrooted environment, significantly reducing the impact to the rest of the system. How-to's exist for popular Linux network services and a quick search on Google will find those.

Conclusion

The rate of exploit attempts and network worms is rising and will continue to rise. The attack vectors are continually increasing in their sophistication, and attacks are becoming much more difficult to prevent or even contain. Both Linux and Windows can be made insecure in a network environment - and both can also be made secure enough to be safe. Regardless of your chosen platform, the most important tool available to you is an effective combination of your staff, proper procedures, and technology.

More Stories By Brad Doctor

Brad Doctor, CISSP, is StillSecure's director of security research. He has been involved in IT security for more than 10 years. Prior to StillSecure, Brad consulted for such companies as Apple Computer, Phoenix Technologies,
and the Monster Board, fulfilling network and host-based security needs. In addition to traditional IT security, Brad also worked with Quova, Inc., as the director of research.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
SYS-CON Events announced today that IDenticard will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. IDenticard™ is the security division of Brady Corp (NYSE: BRC), a $1.5 billion manufacturer of identification products. We have small-company values with the strength and stability of a major corporation. IDenticard offers local sales, support and service to our customers across the United States and Canada. Our partner network encompasses some 300 of the world's leading systems integrators and security s...
SYS-CON Events announced today the IoT Bootcamp – Jumpstart Your IoT Strategy, being held June 9–10, 2015, in conjunction with 16th Cloud Expo and Internet of @ThingsExpo at the Javits Center in New York City. This is your chance to jumpstart your IoT strategy. Combined with real-world scenarios and use cases, the IoT Bootcamp is not just based on presentations but includes hands-on demos and walkthroughs. We will introduce you to a variety of Do-It-Yourself IoT platforms including Arduino, Raspberry Pi, BeagleBone, Spark and Intel Edison. You will also get an overview of cloud technologies s...
“In the past year we've seen a lot of stabilization of WebRTC. You can now use it in production with a far greater degree of certainty. A lot of the real developments in the past year have been in things like the data channel, which will enable a whole new type of application," explained Peter Dunkley, Technical Director at Acision, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The best mobile applications are augmented by dedicated servers, the Internet and Cloud services. Mobile developers should focus on one thing: writing the next socially disruptive viral app. Thanks to the cloud, they can focus on the overall solution, not the underlying plumbing. From iOS to Android and Windows, developers can leverage cloud services to create a common cross-platform backend to persist user settings, app data, broadcast notifications, run jobs, etc. This session provides a high level technical overview of many cloud services available to mobile app developers, includi...
SYS-CON Events announced today that Ciqada will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Ciqada™ makes it easy to connect your products to the Internet. By integrating key components - hardware, servers, dashboards, and mobile apps - into an easy-to-use, configurable system, your products can quickly and securely join the internet of things. With remote monitoring, control, and alert messaging capability, you will meet your customers' needs of tomorrow - today! Ciqada. Let your products take flight. For more inform...
Containers and microservices have become topics of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 16th Cloud Expo at the Javits Center in New York June 9-11 will find fresh new content in a new track called PaaS | Containers & Microservices Containers are not being considered for the first time by the cloud community, but a current era of re-consideration has pushed them to the top of the cloud agenda. With the launch of Docker's initial release in March of 2013, interest was revved up several notches. Then late last...
Health care systems across the globe are under enormous strain, as facilities reach capacity and costs continue to rise. M2M and the Internet of Things have the potential to transform the industry through connected health solutions that can make care more efficient while reducing costs. In fact, Vodafone's annual M2M Barometer Report forecasts M2M applications rising to 57 percent in health care and life sciences by 2016. Lively is one of Vodafone's health care partners, whose solutions enable older adults to live independent lives while staying connected to loved ones. M2M will continue to gr...
Dave will share his insights on how Internet of Things for Enterprises are transforming and making more productive and efficient operations and maintenance (O&M) procedures in the cleantech industry and beyond. Speaker Bio: Dave Landa is chief operating officer of Cybozu Corp (kintone US). Based in the San Francisco Bay Area, Dave has been on the forefront of the Cloud revolution driving strategic business development on the executive teams of multiple leading Software as a Services (SaaS) application providers dating back to 2004. Cybozu's kintone.com is a leading global BYOA (Build Your O...
While not quite mainstream yet, WebRTC is starting to gain ground with Carriers, Enterprises and Independent Software Vendors (ISV’s) alike. WebRTC makes it easy for developers to add audio and video communications into their applications by using Web browsers as their platform. But like any market, every customer engagement has unique requirements, as well as constraints. And of course, one size does not fit all. In her session at WebRTC Summit, Dr. Natasha Tamaskar, Vice President, Head of Cloud and Mobile Strategy at GENBAND, will explore what is needed to take a real time communications ...
SYS-CON Media announced today that @WebRTCSummit Blog, the largest WebRTC resource in the world, has been launched. @WebRTCSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @WebRTCSummit Blog can be bookmarked ▸ Here @WebRTCSummit conference site can be bookmarked ▸ Here
SYS-CON Events announced today that GENBAND, a leading developer of real time communications software solutions, has been named “Silver Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. The GENBAND team will be on hand to demonstrate their newest product, Kandy. Kandy is a communications Platform-as-a-Service (PaaS) that enables companies to seamlessly integrate more human communications into their Web and mobile applications - creating more engaging experiences for their customers and boosting collaboration and productiv...
SYS-CON Events announced today that BroadSoft, the leading global provider of Unified Communications and Collaboration (UCC) services to operators worldwide, has been named “Gold Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. BroadSoft is the leading provider of software and services that enable mobile, fixed-line and cable service providers to offer Unified Communications over their Internet Protocol networks. The Company’s core communications platform enables the delivery of a range of enterprise and consumer calling...
What exactly is a cognitive application? In her session at 16th Cloud Expo, Ashley Hathaway, Product Manager at IBM Watson, will look at the services being offered by the IBM Watson Developer Cloud and what that means for developers and Big Data. She'll explore how IBM Watson and its partnerships will continue to grow and help define what it means to be a cognitive service, as well as take a look at the offerings on Bluemix. She will also check out how Watson and the Alchemy API team up to offer disruptive APIs to developers.
The IoT Bootcamp is coming to Cloud Expo | @ThingsExpo on June 9-10 at the Javits Center in New York. Instructor. Registration is now available at http://iotbootcamp.sys-con.com/ Instructor Janakiram MSV previously taught the famously successful Multi-Cloud Bootcamp at Cloud Expo | @ThingsExpo in November in Santa Clara. Now he is expanding the focus to Janakiram is the founder and CTO of Get Cloud Ready Consulting, a niche Cloud Migration and Cloud Operations firm that recently got acquired by Aditi Technologies. He is a Microsoft Regional Director for Hyderabad, India, and one of the f...
The 17th International Cloud Expo has announced that its Call for Papers is open. 17th International Cloud Expo, to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, APM, APIs, Microservices, Security, Big Data, Internet of Things, DevOps and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal today!
So I guess we’ve officially entered a new era of lean and mean. I say this with the announcement of Ubuntu Snappy Core, “designed for lightweight cloud container hosts running Docker and for smart devices,” according to Canonical. “Snappy Ubuntu Core is the smallest Ubuntu available, designed for security and efficiency in devices or on the cloud.” This first version of Snappy Ubuntu Core features secure app containment and Docker 1.6 (1.5 in main release), is available on public clouds, and for ARM and x86 devices on several IoT boards. It’s a Trend! This announcement comes just as...
SYS-CON Media announced today that @ThingsExpo Blog launched with 7,788 original stories. @ThingsExpo Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @ThingsExpo Blog can be bookmarked. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago.
The world's leading Cloud event, Cloud Expo has launched Microservices Journal on the SYS-CON.com portal, featuring over 19,000 original articles, news stories, features, and blog entries. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. Microservices Journal offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. Follow new article posts on Twitter at @MicroservicesE
SYS-CON Events announced today that robomq.io will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. robomq.io is an interoperable and composable platform that connects any device to any application. It helps systems integrators and the solution providers build new and innovative products and service for industries requiring monitoring or intelligence from devices and sensors.
Wearable technology was dominant at this year’s International Consumer Electronics Show (CES) , and MWC was no exception to this trend. New versions of favorites, such as the Samsung Gear (three new products were released: the Gear 2, the Gear 2 Neo and the Gear Fit), shared the limelight with new wearables like Pebble Time Steel (the new premium version of the company’s previously released smartwatch) and the LG Watch Urbane. The most dramatic difference at MWC was an emphasis on presenting wearables as fashion accessories and moving away from the original clunky technology associated with t...