The Future of Zero Trust and SASE is Now! Watch on-demand

close
close
  • Why Netskope chevron

    Changing the way networking and security work together.

  • Our Customers chevron

    Netskope serves more than 3,000 customers worldwide including more than 25 of the Fortune 100

  • Our Partners chevron

    We partner with security leaders to help you secure your journey to the cloud.

Highest in Execution. Furthest in Vision.

Netskope recognized as a Leader in the 2023 Gartner® Magic Quadrant™ for Security Service Edge.

Get the report
Netskope recognized as a Leader in the 2023 Gartner® Magic Quadrant™ for Security Service Edge.
We help our customers to be Ready for Anything

See our customers
Woman smiling with glasses looking out window
Netskope’s partner-centric go-to-market strategy enables our partners to maximize their growth and profitability while transforming enterprise security.

Learn about Netskope Partners
Group of diverse young professionals smiling
Your Network of Tomorrow

Plan your path toward a faster, more secure, and more resilient network designed for the applications and users that you support.

Get the white paper
Your Network of Tomorrow
Introducing the Netskope One Platform

Netskope One is a cloud-native platform that offers converged security and networking services to enable your SASE and zero trust transformation.

Learn about Netskope One
Abstract with blue lighting
Embrace a Secure Access Service Edge (SASE) architecture

Netskope NewEdge is the world’s largest, highest-performing security private cloud and provides customers with unparalleled service coverage, performance and resilience.

Learn about NewEdge
NewEdge
Netskope Cloud Exchange

The Netskope Cloud Exchange (CE) provides customers with powerful integration tools to leverage investments across their security posture.

Learn about Cloud Exchange
Netskope video
The platform of the future is Netskope

Intelligent Security Service Edge (SSE), Cloud Access Security Broker (CASB), Cloud Firewall, Next Generation Secure Web Gateway (SWG), and Private Access for ZTNA built natively into a single solution to help every business on its journey to Secure Access Service Edge (SASE) architecture.

Go to Products Overview
Netskope video
Next Gen SASE Branch is hybrid — connected, secured, and automated

Netskope Next Gen SASE Branch converges Context-Aware SASE Fabric, Zero-Trust Hybrid Security, and SkopeAI-powered Cloud Orchestrator into a unified cloud offering, ushering in a fully modernized branch experience for the borderless enterprise.

Learn about Next Gen SASE Branch
People at the open space office
Designing a SASE Architecture For Dummies

Get your complimentary copy of the only guide to SASE design you’ll ever need.

Get the eBook
Make the move to market-leading cloud security services with minimal latency and high reliability.

Learn about NewEdge
Lighted highway through mountainside switchbacks
Safely enable the use of generative AI applications with application access control, real-time user coaching, and best-in-class data protection.

Learn how we secure generative AI use
Safely Enable ChatGPT and Generative AI
Zero trust solutions for SSE and SASE deployments

Learn about Zero Trust
Boat driving through open sea
Netskope achieves FedRAMP High Authorization

Choose Netskope GovCloud to accelerate your agency’s transformation.

Learn about Netskope GovCloud
Netskope GovCloud
  • Resources chevron

    Learn more about how Netskope can help you secure your journey to the cloud.

  • Blog chevron

    Learn how Netskope enables security and networking transformation through security service edge (SSE)

  • Events and Workshops chevron

    Stay ahead of the latest security trends and connect with your peers.

  • Security Defined chevron

    Everything you need to know in our cybersecurity encyclopedia.

Security Visionaries Podcast

Elections, Disinformation, and Security
This episode takes a look at aspects of election security around voter registration and physical controls at polling places.

Play the podcast
Blog: Elections, Disinformation, and Security
Latest Blogs

Read how Netskope can enable the Zero Trust and SASE journey through security service edge (SSE) capabilities.

Read the blog
Sunrise and cloudy sky
SASE Week 2023: Your SASE journey starts now!

Replay sessions from the fourth annual SASE Week.

Explore sessions
SASE Week 2023
What is Security Service Edge?

Explore the security side of SASE, the future of network and protection in the cloud.

Learn about Security Service Edge
Four-way roundabout
  • Company chevron

    We help you stay ahead of cloud, data, and network security challenges.

  • Leadership chevron

    Our leadership team is fiercely committed to doing everything it takes to make our customers successful.

  • Customer Solutions chevron

    We are here for you and with you every step of the way, ensuring your success with Netskope.

  • Training and Certification chevron

    Netskope training will help you become a cloud security expert.

Supporting sustainability through data security

Netskope is proud to participate in Vision 2045: an initiative aimed to raise awareness on private industry’s role in sustainability.

Find out more
Supporting Sustainability Through Data Security
Thinkers, builders, dreamers, innovators. Together, we deliver cutting-edge cloud security solutions to help our customers protect their data and people.

Meet our team
Group of hikers scaling a snowy mountain
Netskope’s talented and experienced Professional Services team provides a prescriptive approach to your successful implementation.

Learn about Professional Services
Netskope Professional Services
Secure your digital transformation journey and make the most of your cloud, web, and private applications with Netskope training.

Learn about Training and Certifications
Group of young professionals working

A Real-World Look at AWS Best Practices: Networking

Sep 07 2021

Introduction

Best practices for securing an AWS environment have been well-documented and generally accepted, such as in AWS’s guidance. However, organizations may still find it challenging on how to begin applying this guidance to their specific environments.

  • Which controls should be applied out-of-the-box vs. customized?
  • What pitfalls exist in implementing the various controls or checks?
  • How do you prioritize remediation of the “sea of red” violations?

In this blog series, we’ll analyze anonymized data from Netskope customers that include security settings of 650,000 entities from 1,143 AWS accounts across several hundred organizations. We’ll look at the configuration from the perspective of the best practices, see what’s commonly occurring in the real world and:

  • Discuss specific risk areas that should be prioritized
  • Identify underlying root causes and potential pitfalls
  • Focus on practical guidance for applying the Benchmark to your specific environment

This blog post focuses on IAM security controls related to networking. Based on the analysis, we will highlight two opportunities to improve security by making these networking changes:

  1. Use More Secure Remote Access: Replace security groups that allow inbound Internet access to remote admin ports with more secure methods to remotely administer EC2 instances. 4% of the security groups in use allow inbound Internet access for SSH or RDP. 
  2. Do Not Use Default Security Groups: Ensure that default security groups do not allow any traffic and are not used. 609 default security groups (1% of all security groups) are being used and allow traffic of some kind.

Networking

These three technical controls relating to network security were analyzed against 16,059 network ACLs and 59,361 security groups in 1,143 accounts:

#Best Practice# Violations%
1No NACLs allow ingress from 0.0.0.0/0 to remote admin ports15,77898.3
2No SGs allow ingress from 0.0.0.0/0 to remote admin ports2,3804.0
3Default SGs should restrict all traffic6091.0

1. NACLs

Background: NACLs apply to a particular subnet of a VPC and can be used in combination with security groups to control access to resources within the VPC. They allow all traffic in and out of the VPC by default, are stateless, and specify both allow and deny rules. One can implement defense-in-depth by using both NACLs and security groups.

Data: 15,778 (98%) out of the 16,059 NACLs across 92% of the accounts in this dataset allow Internet access from the Internet to either SSH or RDP.

Analysis: In this dataset, NACLs are not commonly used for filtering inbound internet traffic since almost all NACLs (15,778 or 98%) are configured to allow inbound traffic to SSH or RDP, while a much smaller number of security groups actually allow that same traffic through (2,380 or 4%). If organizations in this dataset are using NACLs for layered defense, then almost all of the NACLs NACLs should implement deny ACLs for inbound Internet traffic to ports 22 and 3389. On the other hand, if NACLs are not being used, then the next two controls regarding Security Groups should be the focus.

Controls:

    • Detection/Audit

      If NACLs are used, then regular and automated checks on NACL rules should be done in order to prevent misconfigured NACLs that allow too much traffic in or out of VPCs.NACLs can be inspected manually in the AWS Console or via the CLI:

      • aws ec2 describe-network-acls
    • Prevention/Mitigation
      Network ACLs can be set in the Console via CLI:

      • aws ec2 create-network-acl
      • aws ec2 create-network-acl-entry

2. Security Groups

Background: Security groups are used to control granular access to instances within a VPC. Best practices are to not allow inbound access to remote administration ports like SSH or RDP.

Data: 2,380 security groups in use allow inbound traffic to port 22 (SSH) or 3389 (RDP).Analysis: When looking at all security groups, 6,527 (11%) allow inbound Internet traffic to SSH or RDP ports. This occurs in about half (48%) of the accounts. The breakdown of the 6,527 security groups into attached vs. unattached is:

Analysis: When looking at all security groups, 6,527 (11%) allow inbound Internet traffic to SSH or RDP ports. This occurs in about half (48%) of the accounts. The breakdown of the 6,527 security groups into attached vs. unattached is:

DescriptionNotes# SGs%
Security Groups allowing ingress from 0.0.0.0/0 to remote admin portsports 22 or 33896,527100
Attachedin use2,38036
Not attachednot in use4,14764

From a remediation perspective, unattached security groups may not be as critical as attached ones as they are unused. However, unused objects of any kind should be reviewed and removed, as they can accidentally be used in the future or may waste time with maintenance and upkeep.

Allowing direct SSH or RDP access to a VPC via a security group is not the most secure way to do remote administration. The drawbacks of this approach include protocol attacks such as SSH multiplexing attacks, exposure of additional ports to the internet, lack of centralized logging, and lack of IAM authentication/access control. This is discussed in detail in: Leaving Bastion Hosts Behind Part 2: AWS.

Controls: 

  • Detection/Audit
    • Regular, automated checks should be implemented to ensure security groups do not allow inbound Internet traffic to remote administration ports.
    • The security groups for an EC2 instance can be checked in the Console or with the CLI:
      • aws ec2 describe-security-groups
    • AWS Config has two rules to detect security groups that allow either SSH or common ports such as RDP.
  • Prevention/Mitigation
    • Instead of exposing ports to inbound Internet traffic, use better solutions for private access to EC2 instances for remote administration. Alternatives include AWS Session Manager or products such as Netskope Private Access.

3. Default Security Groups

Background: There are two best practices related to default security groups.

  1. Default security groups should not allow any traffic inbound or outbound
    By default, all traffic to/from EC2 instances should be prevented, which forces conscious decisions to be made for which traffic is allowed. Since default security groups don’t allow any traffic, the corollary to this is: do not modify default security groups. It can only lead to confusion and errors.
  2. Don’t use default security groups
    Instead of using and modifying default security groups, create new, customized ones for your EC2 instances, which practices a principle of conscious, explicit policies rather than implicit, default policies.

Data: In this dataset, 609 default security groups in use allow traffic, which is 1% of all security groups.

Analysis: We will break down the default 10,307 default security groups to identify which are attached to a network interface (and being used) or not, since both sets are worth looking at for security reasons.

DescriptionNotes# SGs%
Default security groups allowing traffic inbound or outboundHave at least 1 inbound or 1 outbound rule10,307100
Attachedin use6096
Not attachednot in use9,69895

Attached default security groups should be remediated immediately by replacing them with customized security groups. 

Unattached or unused security groups of any kind should also be reviewed. Best practices guidance is to remove all rules from default security groups and ensure they are not attached to any resources.

Controls:

  • Detection/Audit
    • Regular and automated checks should be implemented to detect default security group usage, and these should be replaced with custom security groups instead.
    • The AWS Console and CLI can be used to audit security groups:
      • aws ec2 describe-security-groups
    • Default security groups are named “default” and all attached default security groups should be reviewed.
    • AWS Config also has a rule to detect if the default security group allows traffic.
  • Prevention/Mitigation
    • Ensure that the EC2 provisioning process uses or creates custom security groups and attaches that to a new EC2 instance.

Conclusion

The CIS Foundation Benchmark for AWS provides specific guidance on auditing and remediating your configurations in these areas. There are some basic measures that can be done to address some of the common risk areas due to storage or network configuration in your AWS environment:

  1. Secure Remote Admin: Instead of remotely administering and accessing compute instances by opening up security groups, use more secure methods to remotely administer EC2 instances such as AWS Session Manager or Netskope Private Access.
  2. Do Not Use Default Security Groups: Do not use default security groups.

Dataset and Methodology

Time Period: Data was sampled/analyzed from January 24, 2021. 

Source: The analysis presented in this blog post is based on anonymized usage data collected by the Netskope Security Cloud platform relating to a subset of Netskope customers with prior authorization.

Data Scope: The data included 1,143 AWS accounts and several hundred organizations. 

The data was composed of configuration settings across tens of thousands of AWS entities including IAM users, IAM policies, password policy, buckets, databases, CloudTrail logs, compute instances, and security groups.

Logic: The analysis followed the logic of core root account security checks found in best practices regarding AWS configuration settings.

author image
Jenko Hwong
Jenko has 15+ years of experience in research, product management, and engineering in cloud security, AV/AS, routers/appliances, threat intel, Windows security, vulnerability scanning and compliance. At Netskope, he researches new cloud attacks.

Stay informed!

Subscribe for the latest from the Netskope Blog