A few days ago, Google identified a vulnerability in the design of SSL 3.0. This vulnerability allows the plaintext of secure connections to be calculated by a network attacker. This issue was discovered by Bodo Moller in collaboration with Thai Duong and Krzysztof Kotowicz (also Googlers). The attack has been named as the POODLE bites attack, standing for Padding Oracle On Downgraded Legacy Encryption. Check out the document available on the OpenSSL website to learn more about this vulnerability.
What is POODLE?
To maintain compatibility with legacy servers, many TLS clients implement a downgrade dance: in a first handshake attempt, offer the highest protocol version supported by the client; if this handshake fails, they retry (possibly repeatedly) with earlier protocol versions. Unlike proper protocol version negotiation (if the client offers TLS 1.2, the server may respond with, say, TLS 1.0), this downgrade can also be triggered by network glitches, or by active attackers. So if an attacker that controls the network between the client and the server interferes with any attempted handshake offering TLS 1.0 or later, such clients will readily confine themselves to SSL 3.0.
Encryption in SSL 3.0 uses either the RC4 stream cipher or a block cipher in CBC mode. RC4 is well known to have biases, meaning that if the same secret (such as a password or HTTP cookie) is sent over many connections and thus encrypted with many RC4 streams, more and more information about it will leak.
Unlike with the BEAST and Lucky 13 attacks, there is no reasonable workaround. This leaves us with no secure SSL 3.0 cipher suites at all: to achieve secure encryption, SSL 3.0 must be avoided entirely.
Does POODLE have an impact on cloud environments?
Any system using SSL 3.0 might fall under this attack. Right now, all the Cloud service providers are acting on this vulnerability and updated their customers to close the doors towards the attack.
Amazon AWS Cloud has two public facing services called Elastic Load Balancer (ELB) and CloudFront, both using the SSLV3 protocol to serve the requests via the secured channel. Generally, the customers themselves will manage the SSL configurations in these two services. To mitigate the POODLE attacks on these two services, we have to disable the SSLV3 Support.
Disable the SSLV3 Protocol to handle POODLE on Amazon AWS ELB
All the ELBs which are created after 10/14/2014 5:00 PM PDT will use a new SSL Negotiation Policy that will by default no longer enable SSLv3.
For the existing ELBs, it’s necessary to manually disable SSLv3 via the AWS Management console:
- Select your load balancer (EC2 -> Load Balancers) in the appropriate region
- In the Listeners tab, click “Change” in the Cipher column.|
- Ensure that the radio button for “Predefined Security Policy” is selected, in the dropdown select the “ELBSecurityPolicy-2014-10” policy. You can see the Protocol-SSLV3 is unchecked after selecting the policy.
- Click “Save” to apply the settings to the listener
- Repeat these steps for each listener that is using HTTPS or SSL for each LoadBalancer.
If you require the SSLv3 support you can re-enable it by selecting the “ELBSecurityPolicy-2014-10” Policy or manually configure the SSL ciphers and protocols as per your requirements. Nevertheless, this will expose you again to POODLE, so you should consider this opportunity very carefully
Disable the SSLv3 Protocol to handle POODLE attacks on Cloud Front
Similarly to Amazon ELB, Amazon AWS has taken care of the issue disabling SSLv3 for the customers who use the default SSL settings. Nevertheless, customers who are using custom SSL certificates with Amazon Cloud Front should disable the SSLv3 protocol manually by following the steps below in the Amazon CloudFront Management Console:
- Select your distribution, then click “Distribution Settings”.
- Click the “Edit” button on the “General” tab.
- In the “Custom SSL Client Support” section, select the option that says: “Only Clients that Support Server Name Indication (SNI)”.
- Click “Yes, Edit” to save these revised settings.
AWS API endpoints are not affected by the attack described in the POODLE paper. Instead of using cookies to authenticate users, a unique signature is computed for every request. No action is required from customers that use the AWS SDK or other SDKs to access our API endpoints.
New Content: Azure DP-100 Certification, Alibaba Cloud Certified Associate Prep, 13 Security Labs, and Much More
This past month our Content Team served up a heaping spoonful of new and updated content. Not only did our experts release the brand new Azure DP-100 Certification Learning Path, but they also created 18 new hands-on labs — and so much more! New content on Cloud Academy At any time, y...
AWS Certification Practice Exam: What to Expect from Test Questions
If you’re building applications on the AWS cloud or looking to get started in cloud computing, certification is a way to build deep knowledge in key services unique to the AWS platform. AWS currently offers 12 certifications that cover major cloud roles including Solutions Architect, De...
Overcoming Unprecedented Business Challenges with AWS
From auto-scaling applications with high availability to video conferencing that’s used by everyone, every day — cloud technology has never been more popular or in-demand. But what does this mean for experienced cloud professionals and the challenges they face as they carve out a new p...
Constant Content: Cloud Academy’s Q3 2020 Roadmap
Hello — Andy Larkin here, VP of Content at Cloud Academy. I am pleased to release our roadmap for the next three months of 2020 — August through October. Let me walk you through the content we have planned for you and how this content can help you gain skills, get certified, and...
New Content: Alibaba, Azure AZ-303 and AZ-304, Site Reliability Engineering (SRE) Foundation, Python 3 Programming, 16 Hands-on Labs, and Much More
This month our Content Team did an amazing job at publishing and updating a ton of new content. Not only did our experts release the brand new AZ-303 and AZ-304 Certification Learning Paths, but they also created 16 new hands-on labs — and so much more! New content on Cloud Academy At...
Blog Digest: Which Certifications Should I Get?, The 12 Microsoft Azure Certifications, 6 Ways to Prevent a Data Breach, and More
This month, we were excited to announce that Cloud Academy was recognized in the G2 Summer 2020 reports! These reports highlight the top-rated solutions in the industry, as chosen by the source that matters most: customers. We're grateful to have been nominated as a High Performer in se...
Which Certifications Should I Get?
The old AWS slogan, “Cloud is the new normal” is indeed a reality today. Really, cloud has been the new normal for a while now and getting credentials has become an increasingly effective way to quickly showcase your abilities to recruiters and companies. With all that in mind, the s...
New Content: AWS, Azure, Typescript, Java, Docker, 13 New Labs, and Much More
This month, our Content Team released a whopping 13 new labs in real cloud environments! If you haven't tried out our labs, you might not understand why we think that number is so impressive. Our labs are not “simulated” experiences — they are real cloud environments using accounts on A...
Kickstart Your Tech Training With a Free Week on Cloud Academy
Are you looking to make a jump in your technical career? Want to get trained or certified on AWS, Azure, Google Cloud Platform, DevOps, Kubernetes, Python, or another in-demand skill? Then you'll want to mark your calendar. Starting Monday, June 22 at 12:00 a.m. PDT (3:00 a.m. EDT), ...
New Content: AZ-500 and AZ-400 Updates, 3 Google Professional Exam Preps, Practical ML Learning Path, C# Programming, and More
This month, our Content Team released tons of new content and labs in real cloud environments. Not only that, but we introduced our very first highly interactive "Office Hours" webinar. This webinar, Acing the AWS Solutions Architect Associate Certification, started with a quick overvie...
Azure vs. AWS: Which Certification Provides the Brighter Future?
More and more companies are using cloud services, prompting more and more people to switch their current IT position to something cloud-related. The problem is most people only have that much time after work to learn new technologies, and there are plenty of cloud services that you can ...
Blog Digest: 5 Reasons to Get AWS Certified, OWASP Top 10, Getting Started with VPCs, Top 10 Soft Skills, and More
Thank you for being a valued member of our community! We recently sent out a short survey to understand what type of content you would like us to add to Cloud Academy, and we want to thank everyone who gave us their input. If you would like to complete the survey, it's not too late. It ...