Securing your Cloud Stack from Ransomware

For enterprises that use the cloud, the key to being protected starts with understanding the layers that make up the components of their cloud stack. These different layers create multiple potential targets, and for the informed, they each represent a piece of the cloud environment that can be secured against potential threats.

Ransomware, for example, doesn't have to be terribly complex stuff. To be effective, it just needs access. By paying attention to the different pieces of the cloud stack, and addressing their unique security needs, your environment can be far more resistant to ransomware threats.

Identity Management
Besides enforcing secure passwords and multifactor authentication (MFA), apply the "least privilege roles" concept: Only give users access to the least amount of accounts and systems that allow them to be productive. This limits the damage that can be done if an accident is made or a bad actor gets access to the account. 

Secure the Cloud Compute Layer
Take steps to secure your compute layer to ensure availability of systems and data, and to keep bad actors from using your compute power to further spread malware across your business and the Internet. The first step here is to enable secure login by issuing SSH keys issued to individuals.

Use a Jump Host
A jump host is placed in a different security zone and provides the only means of accessing other servers or hosts in your system. It is an extra step that will add a layer of security complexity to keep hackers out of your system. As the single administrative entry point, be sure to take steps to protect this server and maintain strict access controls. Also, be sure to turn on logging so you can audit all activity. But, if this one server gets owned, the jump server will allow you to create a new one with the push of a button.

Create Hypervisor Firewall Rules
The most effective way to manage firewalls is at the hypervisor level because you can restrict or set limits on both ingress and egress traffic. Take care to set definitive rules about what, how much, and who can send, receive, and access both inbound and outbound data. Many are reluctant to set up outbound rules, but because ransomware often threatens the leaking of your intellectual property, it is important to ensure you have outbound rules that are explicitly declared.

Only Use Trusted Images
Build your images or templates from scratch or get them from very trusted sources like AWS or Microsoft. Don’t use the ones you find on Stackoverflow or on random message boards or communities. The hackers have gotten clever enough to respond to hot topics and embed malware into packages and templates.

Manage Data Access for Cloud Storage
Identity and Access Policies (IAM) policies and Access Control Lists help you centralize the control of permissions to your storage.  Bucket policies allow you to enable or deny permissions by accounts, users, or based on certain conditions like date, IP address, or whether the request was sent with SSL. 

Encrypt, Encrypt, Encrypt
When using public cloud infrastructure, it is imperative that your data is encrypted both in transit and at rest. There are many great encryption tools and services that will help with each. Note that the metadata (the data describing what you’re storing) is often not encrypted, so be sure not to store sensitive information in your cloud storage metadata.

No Delete Rights or MFA for Delete
You can set up roles in your cloud infrastructure that do not allow the user to delete any data. This protects you in case an attacker has gained control of a user’s account. In that case, attackers may be able to access the data, but they can’t delete it, which is usually what is threatened in ransomware attacks. Also, in most cloud storage solutions you can enable a feature that requires the six-digit code and serial number from your MFA token to delete any version of data stored in your storage layer. This means that attackers won’t be able to delete your data if they get access, unless they’ve got your MFA key.

Don’t Allow Services to Call Home to SaaS Systems Like Github
All it takes is for a bad actor to get access to your Git repo, and they can infect and potentially get access to more of your systems the next time one of your systems calls home. A better option is to store your Git or code repositories securely in your own cloud environment.

Our Evident security platform analyzes more than 10 billion events every month, and we see that poor configuration, lack of policies, and permissive behaviors lead to too many openings that are exploitable by ransomware.

For more information on creating an optimal security environment for your cloud environment that will assist in thwarting ransomware through a set of corrective actions and behavioral modifications, click here.