can Ec2 instances from one account access ec2 instance of other account? - amazon-web-services

currently working with two environments/account.
Dev and staging
We are paling to spin up a new instance to install Jenkins for CI/CD in dev environment.
We are also wondering if we can use the same instance which is in dev as a CI/CD for staging account as well.
How will access work?
How can the CI/CD instance access the instances in stating for CI/CD?
Do we need to set up a cross-account role for this which allowed dev CI/CD to access the stating instances?
or
the private key is enough to have access to EC2 irrespective of account?

You can definitely enable this. Take a look at VPC peering.
This features enables 2 VPCs whether different account or different region, to connect to each other as there networks become connected via a tunnel between.
When you implement this the following factors are important:
No cross over of CIDR ranges within VPCs
The VPC peering connection must be added to the route table(s) in both VPCs allowing them to know how to connect to the other VPC.
You will need to whitelist in security groups to allow access fro the instances that you want to be able to connect.
By doing this you also benefit from any network connections traversing the AWS backbone rather than across the public internet which will lead to improvements for security and performance.

Related

Bastion Server for all AWS instances

i have more than 30 production Windows severs in all AWS regions. I would like to connect all servers from one base bastion host. can any one please let me know which one is good choice? How can i setup one bastion host to communicate all servers which is different regions and different VPC's? Kindly anyone give advice for this?
First of all, I would question what are you trying to achieve with a single bastion design? For example, if all you want is to execute automation commands or patches it would be significantly more efficient (and cheaper) to use AWS System Manager Run Commands or AWS System Manager Patch Manager respectively. With AWS System Manager you are getting a managed service that offers advance management capabilities with highest security principles built-in. Additionally, with SSM almost all access permissions could be regulated via IAM permission policies.
Still, if you need to set-up bastion host for some other purpose not supported by SSM, the answer includes several steps that you need to do.
Firstly, since you are dealing with multiple VPCs (across regions), one way to connect them all and access them from you bastion's VPC would be to set-up a Inter-Region Transit Gateway. However, among other, you would need to make sure that your VPC (and Subnet) CIDR ranges are not overlapping. Otherwise, it will be impossible to properly arrange routing tables.
Secondly, you need to arrange that access from your bastion is allowed in the inbound connections of your target's security group. Since, you are dealing with peered VPCs you will need to properly allow your inbound access based on CIDR ranges.
Finally, you need to decide how you will secure access to your Windows Bastion host. Like with almost all use-cases relying on Amazon EC2 instances, I would stress to keep all the instances in private subnets. From private subnets you can always reach the internet via NAT Gateways (or NAT Instances) and stay protected from unauthorized external access attempts. Therefore, if your Bastion is in private subnet you could use the capability of SSM to establish a port-forwarding session to your local machine. In this way, you enable yourself the connection while even your bastion is secured in private subnet.
Overall, this answer to your question involves a lot of complexity and components that will definitely incur charges to your AWS account. So, it would be wise to consider what practical problem are you trying to solve (not shared in the question)? Afterwards, you could evaluate if there is an applicable managed service like SSM that is already provided by AWS. In the end, from a security perspective, granting access to all instances from a single bastion might not be best practice. If you consider scenarios in which you bastion is compromised for whatever reason, you basically compromised all of your instances across all of the regions.
Hope it gives you slightly better understanding of your potential solution.

Alternative to AWS's Security groups in GCP?

Is there an alternative to AWS's security groups in the Google Cloud Platform?
Following is the situation which I have:
A Basic Node.js server running in Cloud Run as a docker image.
A Postgres SQL database at GCP.
A Redis instance at GCP.
What I want to do is make a 'security group' sort of so that my Postgres SQL DB and Redis instance can only be accessed from my Node.js server and nowhere else. I don't want them to be publically accessible via an IP.
What we do in AWS is, that only services part of a security group can access each other.
I'm not very sure but I guess in GCP I need to make use of Firewall rules (not sure at all).
If I'm correct could someone please guide me as to how to go about this? And if I'm wrong could someone suggest the correct method?
GCP has firewall rules for its VPC that work similar to AWS Security Groups. More details can be found here. You can place your PostgreSQL database, Redis instance and Node.js server inside GCP VPC.
Make Node.js server available to the public via DNS.
Set default-allow-internal rule, so that only the services present in VPC can access each other (halting public access of DB and Redis)
As an alternative approach, you may also keep all three servers public and only allow Node.js IP address to access DB and Redis servers, but the above solution is recommended.
Security groups inside AWS are instance-attached firewall-like components. So for example, you can have a SG on an instance level, similar to configuring IP-tables on regular Linux.
On the other hand, Google Firewall rules are more on a Network level. I guess, for the level of "granularity", I'd say that Security Groups can be replaced to instance-level granularity, so then your alternatives are to use one of the following:
firewalld
nftables
iptables
The thing is that in AWS you can also attach security groups to subnets. So SG's when attached to subnets, are also kind of similar to google firewalls, still, security groups provide a bit more granularity since you can have different security groups per subnet, while in GCP you need to have a firewall per Network. At this level, protection should come from firewalls in subnets.
Thanks #amsh for the solution to the problem. But there were a few more things that were required to be done so I guess it'll be better if I list them out here if anyone needs in the future:
Create a VPC network and add a subnet for a particular region (Eg: us-central1).
Create a VPC connector from the Serverless VPC Access section for the created VPC network in the same region.
In Cloud Run add the created VPC connector in the Connection section.
Create the PostgreSQL and Redis instance in the same region as that of the created VPC network.
In the Private IP section of these instances, select the created VPC network. This will create a Private IP for the respective instances in the region of the created VPC network.
Use this Private IP in the Node.js server to connect to the instance and it'll be good to go.
Common Problems you might face:
Error while creating the VPC Connector: Ensure the IP range of the VPC connector and the VPC network do not overlap.
Different regions: Ensure all instances are in the same region of the VPC network, else they won't connect via the Private IP.
Avoid changing the firewall rules: The firewall rules must not be changed unless you need them to perform differently than they normally do.
Instances in different regions: If the instances are spread across different regions, use VPC network peering to establish a connection between them.

Why do hostnames of connections to Aurora Serverless come from outside the VPC?

I have a php website running in Beanstalk behind a load balancer.
The website is connecting to a MySQL compatible database running as Aurora Serverless.
Both the elastic beanstalk instance and Aurora is set up in the same VPC.
The VPC CIDR is 10.10.0.0/24
The elastic beanstalk instance has local IP 10.10.0.18
The serverless Aurora cluster is using VPC endpoints in the two subnets of the VPC and their IP addresses are 10.10.0.30 and 10.10.0.75.
Even though Aurora Serverless is limited to only accepting connections from within the VPC, out of habit I have still only granted my user permission if they are coming from the VPC.
So for instance I have granted permissions to 'user'#'10.10.0.%'
When my website tries to connect to the database however it gets permission denied because it is trying to access it with a user that was not granted permission because the host is not in the 10.10.0.0/24 subnet.
Here are some of the errors that I am getting:
Access denied for user 'user'#'10.1.17.79' (using password: YES)
Access denied for user 'user'#'10.1.18.17' (using password: YES)
Access denied for user 'user'#'10.1.19.1' (using password: YES)
Access denied for user 'user'#'10.1.19.177' (using password: YES)
As you can see, none of those hosts are within my VPC.
Is this because the cluster is running in its own VPC, linked to mine via the private links?
And if so, are my only option to use % as the host for users I grant privileges?
Personally I would like to have locked it down to only my VPC just in case Serverless Aurora opens up for connections from the internet in the future.
Don't whitelist to any specific IP addresses like that for RDS. Especially with Aurora serverless where the node IPs can change at a moments notice a it scales you will find there is no way to know the true IP address of the node.
Remember that all the RDS database services technically run within a AWS managed VPC, you do however get an ENI attached to your VPC that allows you to connect to the instance. This allows you to communicate as if the resource is actually created within your VPC.
The best way to enhance security is going to be through security groups and NACLs, combined with using TLS and encryption at rest. Finally ensure your passwords are strong and rotated frequently.
The RDS Best Practices should help you to dive into other practices you can follow to enhance your security.

Limit Amazon AWS Access of Specific EC2/RDS Instances

I have an Amazon EC2 instance and a corresponding RDS instance that I want to keep private. I'd like to keep it so that only myself and the sysadmin can access these instances. I don't want to provide access to other developers.
However, one of my developers is working on a project right now where he needs to create/configure his own EC2/RDS instance. I could have my sysadmin perform this work, but I'd rather have the developer do it for the sake of expediency.
Is there any way to configure a group/role/policy in a way that allows me to keep my current instances private from the new developer, but would allow him to create his own EC2 and RDS instances?
Your question appears to be mixing several security concepts, such as 'private', 'group/role/policy' and 'firewalls'.
An Amazon EC2 instance has several layers of security:
First, there is the ability to login to the EC2 instance. This is managed by you, typically by creating users on the instance (in either Linux or Windows) and associating a password or Public/Private. Only people who have login credentials will be able to access the instance.
Second, there is the ability to reach the instance. Security Groups control which ports are open from which IP address range. Therefore, you could configure a security group to only make the instance accessible from your own IP address or your own private network. Your instance might also be in a private subnet that has no Internet connectivity. This again restricts access to the instance.
A person can therefore only login to an instance if they have login credentials, if the security group(s) permit access on the protocol being used (RDP or SSH) and if the instance is reachable by the user from the Internet or private network.
Similarly, an Amazon Relational Database Service (RDS) instance is protected by:
Login credentials: A master user login is created when the database is launched, but additional users can be added via normal CREATE USER database commands
Security Groups: As with EC2 instances, security groups control what ports are open to a particular range of IP addresses
Network security: As with EC2 instances, an RDS instance can be placed in a private subnet, which is not accessible from the Internet.
Please note that none of the above controls involve Identity and Access Management (IAM) users/groups/roles/policies, which are used to grant access to AWS services, such as the ability to launch an Amazon EC2 instance or an Amazon RDS instance.
So, the fact that you have existing Amazon EC2 and Amazon RDS instances has no impact on the security of any other instances that you choose to launch. If a user cannot access your existing services, then launching more services will not change that situation.
If you wish to give another person the ability to launch new EC2/RDS instances, you can do this by applying an appropriate policy on their IAM User entity. However, you might want to be careful about how much permission you give them, because you might also be granting them the ability to delete your existing instances, change the master password, create and restore snapshots (thereby potentially accessing your data) and change network configurations (potentially exposing your instances to the Internet).
When granting IAM permissions to somebody, it is recommend that you grant least privilege, which means you should only give them the permissions they need and nothing more. If you are unsure about how much permission to give them or how to configure these permissions, you would be wise to have your System Administrator create the instances on their behalf. That way, you are fully aware of what has been done and you have not potentially exposed your systems.
Ok, the best explanation about how things works is in #John Rotestein response. But here a few practical suggestions (that must be considered as an complement to John's response):
You can create separate subnets and give permissions to your
developers to run instances in only one of the the subnets using IAM
Policies; But your developers still can reach your instance and you
must configure so/db/application restrictions.
If your company DO NOT use a shared gateway to the internet, you can
define the Network ACL to limit the access to your exclusive network
using your IP address. If you use a shared gateway, you will not be
able to use this solution;
In the second case, one way to limit the access is put your instance
in a private subnet and create a bastion host in your public subnet
to be used only by you (this solution must be configured to your RDS
instances too). The bastion host will be reachable by your
developers, but you can use a specific Key Pair that only you have
access. Just keep in mind that your instances and RDS will not be
available to the internet;
But I think that the simple solution would be create different
VPC's, one for your team and the other for the development team. In
this solution you can restrict access to all VPC resources to your
developers in the "main" VPC. Off course this also means no internet connection to your instances.

Creating Multiple domains in one VPC, in Amazon AWS

Is it possible to create multiple domains in single Amazon VPC (Virtual Private Cloud) created in Amazon AWS. ?
The domain-name and domain-name-servers are part of an DHCP Options Sets and a single VPC can only have one DHCP Option set at a time, as visible in the AWS Management Console and e.g. documented for ec2-associate-dhcp-options:
After you associate the options with the VPC, any existing instances
and all new instances that you launch in that VPC use the options. [...]
However, if your use case allows, you could create additional VPCs instead - by default you can create 5 VPCs per region, see Amazon VPC Limits.
Assuming you mean multiple IP's as well, the answer to this question is here.
Quoting:
You can now create and attach an additional network interface, known
as an elastic network interface (ENI), to any Amazon EC2 instance in
your VPC for a total of two network interfaces per instance. More
information here
http://aws.typepad.com/aws/2011/12/new-elastic-network-interfaces-in-the-virtual-private-cloud.html
Yours is a good question if for instance, you are trying to broker various web-services.