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Network Security

Jun 26 2020
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The Portnox network security weekly roundup

Weekly Network Security News Roundup – June 26, 2020

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This Week in Network Security

In an effort to help you sift through the endless bombardment of content, news, and events, Portnox is excited to deliver its inaugural weekly network security news roundup. Below, find hand-picked articles, blog posts and more from across the web covering an array of topics, including network security architecture, access control, SD-branch, working remotely and more.

Happy reading and happy Friday!

COVID on the brain…

 

The IoT buzz…

 

The network security generalist…

 

For our MSP/MSSP brethren…

 

New from Portnox…

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UPCOMING WEBINAR: How Mid-Size Enterprises Can Secure WiFi for Employees, Contractors & Guests

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Nov 17 2019
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The Truth About MAC Spoofing

By | Network Security, Threat Detection and Response | No Comments

The threat behind MAC spoofing

When implementing any insurance policy, you need to start with estimating the level of risk, the probability of that risk, and the potential damage should that risk become a reality.

One of the network risks that is often presented to demonstrate the ineffectiveness of 802.1x solutions is the ease of bypassing modern network access control (NAC) by using MAC spoofing. Usually, this involves spoofing the network printer or other vulnerable device.

Now, let’s put aside the fact that network printers today can support certificate or credential-based authentication, and that certain products have remedies against such attempts even when the authentication is based on MAC.

Let’s consider: is MAC spoofing a legitimate threat or an exaggerated, manageable flaw?

But before I try to analyze this risk, I want to point out the biggest advantage a NAC solution can give an organization to cope with modern cyber security threats: the ability to apply dynamic segmentation based on device type or identity.

Without going into too much detail, NAC is one of the only systems that can help you prevent lateral movement, indirectly allowing you to identify breaches and directly helping you to prevent the compromise of your crown jewels.

The threat landscape

Here are some of the most common adversaries when it comes to MAC spoofing:

  • The employee – a disgruntled current or former employee
  • The guest – a contractor, customer, patient, etc. who physically visits your organization for a period of time
  • The hacker – a malicious person trying to attack your network and steal information, causing harm to your organization

And here are the most common attack surfaces:

  • Wifi
  • Wired, ethernet switches

One caveat: most wifi environments contain managed devices. So, for devices that do not have an 802.1x supplicant, and thus does not support certificate-based authentication (or credentials based), it is easy to setup an isolated segment and significantly lower the risk of attack.

As such, we’ll put our focus on examining wired environments, and how they’re vulnerable to the above adversaries.

Adversaries in-depth

Let’s be clear – MAC spoofing requires some technical knowledge to execute, which the non-technical lay person typically does not possess. Those doing it know what they’re doing, and they know it’s wrong.

With that said, it’s important to point out that a lot of damage is caused by the unintended – i.e. people clicking on a link in an email, deleting the wrong record or file, or even dropping a laptop into a pool.

The employee

Employees should be trustworthy. If they’re not, cyber security is likely not your problem. But, when someone is fired, laid off, or even just mistreated at work, there always exists the potential for them to hold a grudge. It’s human nature.

Disgruntled employees can pose a big risk. If an employee still works for an organization and he/she is determined to do damage, that’s a problem that’s nearly impossible to prevent. The network connection alone is not going to stop he/she from stealing data or worse. This individual likely already has access through other corporate devices and the credentials to access whatever data he/she wants.

At the end of the day, however, this individual’s risk of MAC spoofing can be categorized as “very low” with “low” probability and “low” potential for damage. The reason being is that the potential damage done is not necessarily related to network connection. The first line of defense against a disgruntled current of former employees is physical barriers – i.e. locked doors and other physical security.

The guest

A guest visiting your office might want to connect to your network. Most likely, this guest will not go to great lengths to hack your network if they are initially blocked. By supplying a guest network, such as a guest wifi, you will effectively eliminate that risk all together. Thus, like the employee, this individual’s risk of MAC spoofing can be categorized as “very low” for both probability and damage.

The hacker

A hacker will need physical access to your network in order to do his/her job. Today, spearhead attacks can enable hackers to access your networks from afar. Doing so, however, typically requires some sort of motive.

This motivation is often dependent upon the type of business you operate. If you’re in military and defense, for example, you likely have a higher than average risk of being the target of such an attack. The same going for banking and financial services, healthcare and any other industry with highly sensitive and confidential data.

For most organizations, the threat of physical access hacking is typically low, while the potential for damage could be high. Should a retailer fear physical burglary just because a new device has connected to its network? I think not.

In conclusion

For most organizations, the risk of MAC spoofing is almost non-existent. This is usually fairly easy for an auditor to demonstrate, and would appear as part of a comprehensive security report. So in reality, the perception of the threat is that it’s a much larger problem than it actually is.

You can also prevent MAC spoofing by implementing stronger authentication methods that are fairly common today. One of the major roles of NAC is to provide secure authentication and authorization to the network. Thus, even if authentication is somehow breached, authorization serves as a second layer of defense that can limit access by putting potential individuals of risk in a specific “narrow” segment.

The segmentation of specific types of MAC-based devices is a best practice in NAC. Even if spoofing occurs, such a device won’t be able to access a particularly sensitive VLAN, such as those in Finance or HR, if proper segmentation has been established through your network security policies.

Sep 16 2019
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What is Network Access Control (NAC)?

By | Cloud Security, IoT, Network Access Management, Network Security, Our Technology, Threat Detection and Response | No Comments

An Examination of NAC, its Use Cases & its Future

Network Access Control (NAC) sits within the larger field of cybersecurity, and more specifically network security. It is a technology that enables organizations to enact its own unique policy for how and when endpoints (desktops, laptops, smartphones, etc.) can connect to their corporate networks. NAC solutions are typically designed to allow IT security teams to gain visibility of each device trying to access its network, and specifically the type of device and access layer being used (i.e. wifi, wired ports, or VPN).

Today, NAC provides a number of powerful features on top of what it was originally designed for nearly 15 years ago. These include security posture assessments for endpoints, which pinpoints any associated endpoint risks, allowing network security administrators to control network access based on their organization’s risk tolerance threshold.

With the rise of cloud computing, remote workforces, bring-your-own-device (BYOD) policies, and the internet of things (IoT), network access control has become a much more critical part of the larger cybersecurity technology stack at most companies. The technology itself has also evolved quite drastically in response to these emerging trends and their impact on networking and ensuring network security.

Expanding networks makes cloud based access control more important than ever.

The use cases for NAC today are constantly expanding. Network security professionals leverage NAC solutions for network visibility, the discovery of endpoints, security profiling, compliance enforcement, remediation…the list goes on. In general, NAC is designed to do two core tasks: 1) authenticate the endpoint trying to connect to the network, and 2) authorize access based on authentication and posture assessment.

Throughout this piece, we will examine how NAC is being used out in the real world, things to consider when defining your NAC policies, the best way to invest in NAC, and more. Feel free to skip to any section using the links below:

The Value of Network Access Control

Network access control delivers a host of benefits to the organizations that deploy it. Generally speaking, the value unlocked by NAC can be broken into three distinct areas of focus: 1) operational need, 2) security best practices, and 3) regulatory compliance.

A network access control system can be leveraged for a number of operational purposes.

Operational Need

One of the most interesting aspects of NAC is the fact that unlike many other areas of network security, it brings more than just the value of security to the table. In particular, NAC delivers three core operational values:

  • Device Onboarding – Properly connecting and removing new non-managed devices to/from the network.
  • Guest / Contractor Access – Securely granting limited access for third-parties connecting to the network, either for short or long periods of time.
  • Asset Profiling – Identifying which devices exist in your organization and where they are connecting from.

Security Best Practice

The importance of network security goes without saying. Network access control, however, checks the boxes for a variety of IT security best practices, including:

  • WiFi Security – Nearly 20% of SMBs experience a data breach by a former employee who still has WiFi access…make sure you can control all WiFi connections.
  • Visibility – See all devices on your network – no matter device type, location, or access layer used to connect.
  • Containment – The ability to quarantine, block, or provide limited (guest) access to endpoints that do not meet your internal risk policies.
  • Asset Profiling – see above.

Regulatory Compliance

Highly regulated industries like banking, financial services, and healthcare require strict compliance policies when it comes to their networks. NAC helps to deliver this and more through:

  • Posture Assessment – Continually assess the risk posture of connecting devices across the network, no matter location or access layer.
  • Port / Wired Security – Ensuring no un-trusted device can physically connect to the network via wired ports in the office.
  • Segmentation – Properly directing employees into their respective departmental VLANs, or pushing visitors to the guest network.
  • WiFi Security – see above.

Individual Use Cases for Network Access Control

Within each of the three primary areas of value of NAC are a variety of different use cases for NAC. These include…

Device On-Boarding

NAC is frequently used for device onboarding, which is the process of providing new devices with access to the corporate network for the first time. It sounds simple, but it’s anything but. Business units and even departments (think Finance & Accounting, for example) often have their own VLANs since they’re dealing with very sensitive, confidential data.

Network access security is evolving as companies become more and more distributed.

The task of setting up such VLANs and onboarding new devices is just one of dozens of tasks overseen by frequently overburdened IT teams. So, if not done correctly at first, it can open the door to potential network vulnerabilities, such as a person gaining access to a part of the network he/she should not have the privileges for.

At a small scale, managing access manually if often sufficient. For larger organizations, however, this just isn’t sustainable. As a result, many large organizations that don’t have a secure onboarding process will often compromise on network security hygiene.

Guest Access

At some point in the workday, most companies will have non-employees visiting their offices for meetings and business dealings. These guests are typically on-site for brief periods of time but may need wifi access during the course of their stay.

Typically, each organization defines the level of authentication and monitoring they want for their visitors. Common policies include:

  • Disclaimer Only – Notifying the rules for which they might need to abide while using the company network.
  • Pre-Generated Username & Password – Simple authentication for better control of whom is connecting the network
  • Sponsorship – Authentication based on an individual working for the organization. Usually, the sponsor will receive an email to approve the connected guest.

Many organizations offer a guest network, where day-to-day visitors are directed. This approach effectively eliminates the most common threat – someone that is just looking to be connected to the internet. The most common way to implement network access for guests is through the use of a captive portal.

Contractor Access

Additionally, many businesses hire contractors or consultancies to tackle specific projects. These individuals and groups will need network access for extended periods of time and will need to be granted access to company resources and sensitive, proprietary data. NAC is used to dictate and enforce the level of access these types of individuals receive based on internal policies.

BYOD

In recent years, remote work has soared due to a greater demand for mobility and flexibility. This has given rise to the adoption of bring your own device (BYOD) policies within many organizations. Now, while this approach makes operational (and even financial) sense, it does come with a caveat. By allowing employees, contractors, and guests alike to use their own devices to connect to the network, you’re immediately faced with issues like data leakage, malware infections, the mixing of corporate and personal data, and more.

To secure network access, you need to understand how your organization uses devices.

With BYOD, a network access control solution can effectively secure such a fragmented network through multiple methods of authentication, and by making sure device risk posture is valid and continuously remediating any security issues in real-time. First, network security administrators can use a dedicated SSID for employee device authentication – no matter if it’s managed or personal. They can then create a separate SSID for guests and contractors to authenticate those individuals to the guest wifi.

The other option available for authentication is through the use of directory credentials. Integrating tools like Okta or Active Directory with your NAC can allow you to authenticate manage corporate devices through certificates, and personal credentials for BYOD.

Captive Portal

Captive portal is a web page for authenticating users and verifying their device type and posture state. While this method is sufficient for visitors, it is an insufficient solution for employees or permanent visitors on your network. The most common use cases for captive portal are:

  • Guest access
  • Self-service portal for BYOD / IoT on-boarding

It’s important to note that this is an interactive method to access the network, so when non-interactive devices, such as IoT are “pushed” to a captive portal, they can not react and thus can not gain access to the network. In order to use IoT onboarding with a captive portal, the end-user should either register the IoT in the self-service portal or download some form of credentials to be inserted to the IoT device (such as a digital certificate).

Remote Access

For fully remote employees or contractors, companies have traditionally relied on VPNs to establish secure encrypted connections for remote access to the corporate network. A VPN does not stop an endpoint from accessing the network, however – it’s only a way of providing remote network connectivity. By itself, a VPN is missing the ability to authenticate a user – it can not prevent “unhealthy” devices from connecting to the network.

In the instance of remote access, NAC can be layered over the top of a VPN, VDI or other remote access methods, such as a Meraki Z3 Teleworker Gateway, to provide effective authentication and access control, as well as endpoint risk profiling – just like any other access layer (i.e. wifi or wired port).

Device Risk Posture Assessment

Your corporate network is only as strong as its weakest security link. This means continuous risk posture assessment is paramount. By continually monitoring the network, your network and security teams can stay ahead of cyberattacks with the ability to identify new risks in real-time, react to these risks, and take action. In a world with ever-expanding boundaries and an exponential increase in types of endpoints, continuous risk posture assessment must function no matter location, device type, or the type of data is being transferred.

Endpoint Remediation

Having a rapid remediation plan in place will not only help prevent further damage or the lateral spread of attacks but also allow for business continuity. Effective endpoint remediation consists of:

  • Automated Patch Updates Across the Network – Enforce necessary patch, anti-virus, operating system, and application updates across managed and unmanaged endpoints.
  • Immediate Incident Response – Contain ransomware events by remotely disconnecting endpoints from the network without the need for manual intervention.
  • Armed Incident Response Teams – Arm IT professionals and network admins with the ability to remotely take actions on employees’ devices.

The proliferation of IoT devices over the last decade has prompted a growing number of network security concerns. With all of these devices – printers, CCTV cameras, ATMs, MRI machines, etc. – now connected to their respective networks, it’s exponentially expanding corporate threat surfaces.

A NAC solution can be used to control the access of IoT devices.

To combat the many risks posed by these new endpoints, companies are turning to NAC to gain visibility, knowledge, and control over IoT devices – much the same as traditional PCs and VoIP phones based in the office. There is a huge variety of IoT devices, and in general, there’s a serious lack of centralized management with regards to their security posture. Many of these IoT devices still rely on IT security technology from the 1980s, with no password brute force controls and no available patches.

It’s not a question of if vulnerabilities exist on IoT devices, this is a given. Today, it’s a matter of ensuring these devices can be properly controlled to they can’t compromise the network. Currently, the only line of defense is segmenting them out of the network. Making sure only authorized users and devices can access them – this is exactly what NAC solutions are doing in an automatic method.

Regulatory Control

Industries like banking, financial services, and healthcare are typically subject to a plethora of compliance regulations, such as SOX, HIPAA, PCI-DSS, GLBA, and now GDPR. Embedded in many of these regulations are certain network security parameters that necessitate access control so that sensitive personal and confidential information is not compromised.

Once a company has defined its internal network security compliance policies, it needs to implement a network access control solution to put in them into effect in order to continually assess its compliance standing.

Compliance

NAC is used to enforce regulatory policies and maintain compliance across the organization. In practice, this typically means:

  • Understanding how mobile, BYOD, and IoT devices will affect and transform not only the organization but the industry and implementing the right processes and tools control them.
  • Tracking any network related device or program in real-time via a centrally secured platform providing full and actionable visibility.
  • Controlling access to the network and to cloud applications, even based on the geographical locations of users.
  • Ensuring that the business is in compliance with governmental regulations like SOX, PCI DSS, HIPPA, FINRA, FISMA, GLBA among others. Strict compliance will provide legitimacy with clients and partners.

Common Network Access Control Policies

Access Control Policies

Network security teams define and activate access control policies to control device access to the corporate network, which is ultimately based on the device authorization state. Once a device is authorized for network access, a network access policy determines which specific virtual LAN (VLAN) that device or user is directed to. On top of that, the policy also defines, for each type of authorization violation, whether to deny entry or whether to quarantine the device by assigning it to a specific VLAN or apply an ACL.

Risk Assessment Policies

In addition to defining an access control policy, network administrators will typically define a risk assessment policy, which assigns a risk score to each device. This score will indicate the level of risk posed by the device. Depending on the NAC solution in use, these risk scoring systems may differ. A risk assessment policy defines, for each device attribute (such as OS, security posture, geo-location, and more), the risk rating to apply if the device violates the current policy in use. At the end of the day, the risk score is used to determine whether allow, block, or quarantine from accessing the network. This is the backbone of NAC.

Remediation Policies

In some instances, the network security team may define a series of remediation policies. Essentially, a remediation policy consists of unattended corrective and preventive actions (CAPA), automatically applied to devices upon every transmission or on a recurring basis. A remediation policy can be used to reduce devices’ risk scores and increase compliance levels for network access.

Common Network Access Control Concepts

Post-Connect vs. Pre-Connect

Within the world of network access control, “post-connect” refers to a device being allowed to connect to the network and immediately being checked for authentication. If a device does not meet the organizational criteria for authentication, it will be blocked from having access to the network (or access will be limited).

In contrast, “pre-connect” means that authentication decisions are being made before a device is allowed on the network. Only once the device is authenticated will it be granted access to the network based on the policy. 802.1X is a traditional pre-connect method.

In general, a pre-connect approach is more secure since the device is granted access to the network only after identified as an organizationally trusted device. Post-connect is more operational for end-users, as they are granted access to the network before a decision is made.

Agent-Based vs. Agentless

Today, most NAC solutions can perform authentication and authorization without the need of an agent. Agents are typically employed for the following reasons:

  • Risk Posture Assessment – This mainly the case for companies with BYOD policies.
  • Remediation – In order to know if a firewall or anti-virus is out-of-date, you must have an agent.
  • On-Boarding of Unmanaged Devices – Again this mainly applies to BYOD.

In some cases, the agent does not need to live within the network access control solution. Rather, third-party agents such as mobile app management software (MAM/MDM) and services can be leveraged to execute the above functions.

Cloud NAC vs. On-Prem NAC

As we go into further detail below, if you can move NAC to the cloud, you should. There is a myriad of benefits to doing so. At a high-level, these include operational time savings thanks to easier deployment and less on-going maintenance, better accessibility (especially for distributed enterprises), more flexibility as your business needs change, etc. In general, enterprises are increasingly adopting purpose-built cloud technologies for different operational needs, and NAC is no exception.

Not every organization has the ability to deploy a cloud NAC solution, however. One of the main hindrances of doing so is a lack of openness or internal expertise for cloud services. There still remain dwindling concerns, misconceptions and unrealistic expectations over the potential benefits and overall security of public cloud services, which has resulted in some industries such as government agencies, healthcare, and education – to name a few – to be slow in adopting new enterprise cloud technologies.

Passive Profiling vs. Active Profiling

A core function of NAC is the profiling of network traffic and connected devices. In general, there are two approaches to profiling: 1) passive profiling and 2) active profiling.

Passive profiling means that a company’s NAC solution has been allowed to see all traffic across the network, and uses this intelligence to observe and analyze traffic to develop a passive profile of each device. On the other hand, active profiling means that a company’s NAC solution has been configured to initiate requests to the endpoints so that each device can have a profile created for it.

Must-Have Network Access Control Solution Capabilities

Full Access Layer Coverage

As today’s networks explode in size and scope, particularly with remote workforces on the rise, it’s imperative that your NAC solution can manage access control across all existing access layers. This includes the obvious – wired ports and WiFi. It also must be able to manage the various remote access methods used within your organization. These may include VPN, virtual desktop infrastructure (VDI), Meraki Z-Series Teleworker Gateways, and beyond.

Network access control solutions must cover wired ports, wifi and VPN.Cloud-Delivered

Nearly primary management and productivity tool used by businesses have shifted to the cloud. Network access control is no exception. The inherent productivity, operational, economic, and accessibility benefits have driven this trend in the last fifteen years.

When it comes to NAC, however, there is a big difference between cloud-based and cloud-delivered. Some NAC providers offer an accessible cloud-based platform from which to manage network access, but this typically still requires on-site hardware to be installed. With a cloud-delivered approach, you stand up everything from a RADIUS server in the cloud to allow for centralized authentication and authorization up to certificate authority. This saves a significant amount of time and means that even large distributed organizations can implement NAC across their many locations in a fraction of the time as traditional on-premise network access control solutions.

802.1X Authentication

Today, 802.1X is the standard protocol for network access control. When searching for a NAC solution, the ability of the system to deliver 802.1X authentication is of the utmost importance. With access control based on 802.1X, network administrators can confidently block rogue devices, quarantine noncompliant endpoints, limit access to specified resources – whatever your internal policy calls for. 802.1X remains one of the best ways to authenticate devices because of its continuous and direct communication, in contrast to post-scanners, or other less secure authentication solutions that expose the network to vulnerabilities.

Zero-Trust for Endpoints

While “zero-trust” has become another overused buzzword in the world of network security, it is, in fact, an effective approach to sealing your network off from rogue devices. With zero-trust, an organization inherently does not trust any endpoint inside or outside its perimeters. A zero-trust network access control solution can eliminate the need for extensive endpoint scanning since the status of a device is already known. This doesn’t eliminate all of the attack surfaces, but it does help in protecting both endpoints and your network.

Endpoint Risk Assessment

The ability to continuously assess the risk of devices connected to or trying to connect to your network is paramount. Understanding the risk posture of devices – on-site or remote – and proactively taking action based on endpoint risk – such as allowing, quarantining, or denying access across access layers – is the best way to ensure network threats are kept at bay.

The world is changing – threat surface is expanding, and companies are increasingly turning to purpose-built enterprise cloud applications to streamline business processes. Today, it’s not enough to just protect what’s on-premise – you need to know the risk posture assessment of every device that connects to corporate resources, no matter location.

Continuous Device Remediation

Awareness is only a piece of the puzzle, however. When considering a NAC solution, it’s important to understand if it can easily remediate devices that sit outside of internal risk policies and restore those devices to the proper posture to eventually grant network access. Put simply, ensuring devices are healthy reduces security risk. That means network administrators can sleep a bit more soundly at night.

As we covered earlier, real-time device remediation has a major operational benefit as well – it saves time! By eliminating the need for network or security administrators to fix devices manually, you’re freeing them up for more important tasks.

Corrective & Preventative Action (CAPA)

Risky technology behavior like inserting an untrusted USB drive, or failing to update a firewall or anti-virus is prevalent. We’re almost all guilty of it. The ability to prevent this risky behavior is thus important. Not just for the sake of lowering the exposure time, also saving important time for the organization by fixing the issue automatically and preventing a potential breach.

Multi-Factor Authentication (MFA)

Leveraging MFA for NAC that looks at a user’s credentials and an enrolled device is critical to ensuring access control across today’s expanding networks. MFA should be integrated within your NAC, especially on remote access. This approach ensures that security is offered on two levels: protection of the user identity, and authorization of the device – making sure only managed and secure devices are allowed to gain access. With MFA, if a user’s credentials are compromised, they’re effectively useless and if the device being used is not enrolled with the NAC you cannot access the VPN, VDI, or cloud applications.

The Future of Network Access Control

NAC and the Rise of SD-WAN

The adoption of Software-as-a-Service (SaaS) and cloud services has decentralized data traffic flows, making Multiprotocol Label Switching (MPLS) inefficient for wide area network (WAN) transport. This has given rise to SD-WAN for the implementation of software-defined branch (SD-branch), now allowing IT environments to be extended to branches outside of the headquarters that need high-quality network connectivity.

NAC security is evolving with the rise of SD-WAN.Traditionally, in order for NAC to effectively operate, it has needed a direct connection to headquarters and appliances deployed on-site at individual branches. This is a costly, time-consuming endeavor, and has historically limited the use of SD-WAN and SD-branch. NAC has adapted by moving to the cloud, eliminating the need for on-site appliances and on-going maintenance. Now, all one needs is an internet connection to implement.

The Impact of Secure Access Service Edge (SASE) on NAC

In 2019, Gartner introduced SASE as a new enterprise networking technology category. In essence, SASE converges the functions of network and security solutions into a single, unified cloud service. This marks an architectural transformation within the realm of enterprise networking and security, and it means that IT teams can now deliver a holistic and flexible service to their businesses.

Network visibility solutions must take SASE into account.The logical next step in the evolution of network security is for organizations to be able to leverage a NAC solution that’s delivered as a cloud service. This eliminates the need for costly on-site appliances and on-going maintenance. Now, all that’s needed to control network access at branches and the headquarters alike, is an internet connection.