Secure Socket Shell (SSH), also known as Secure Shell, is a networking protocol that uses public-key cryptography to allow approved users to access a computer or other device using SSH keys remotely and therefore using SSH Key Security. These keys must be managed as carefully as sensitive passwords because they are used to access critical resources and perform essential, highly privileged tasks.
Though SSH keys are more common and standard in Unix and Linux environments, their use is also prevalent in Windows systems.
SSH Key Security — Overview
The Secure Shell, as well as the public-key cryptography (an encryption scheme that uses two keys: one public, one private) that SSH keys employ, are intended to provide safe, encrypted communication between a user and a remote machine.
SSH technology is built on the client-server model and is an excellent way to connect to remote computers over insecure networks such as the internet. Administrators usually use technology for a variety of purposes, including:
- Assistance and repair
- Logging into remote computers/servers
- Data transfer from one device to another
- Executing commands remotely
- Providing assistance and alerts
SSH Key Security Best Practices
You can make use of the following five best practices to strengthen security controls around SSH Keys:
Make a list of all SSH keys and place them under active management.
The discovery and inventory of all SSH keys, followed by unified control, is the first step toward removing SSH key sprawl and properly evaluating SSH security danger. It is also an excellent time to figure out who is using which keys and how they are being used.
Ascertain that all SSH keys are linked to a single individual.
SSH keys should be linked to a single person rather than an account that several individuals can access. It would result in a more successful SSH audit trail as well as more direct supervision.
Use PoLP to enact the bare minimum of user rights.
Use the principle of least privilege (PoLP), such as tying SSH keys to granulated areas of remote devices, to limit user access to only those systems that are absolutely required. It mitigates the risk of SSH keys being misused.
Keep an eye on the SSH key rotation.
Implement a strict SSH key rotation scheme, requiring users to create keys on a regular basis and banning the use of the same password through multiple accounts or iterations. These activities aid in the prevention of password re-use attacks within the company. This can only be accomplished through an automated solution in organizations with a broad SSH key estate.
Every Privileged Session Operation Should Be Audited
Apart from the above, any privileged session initiated through SSH Key Security authentication (or other means) should be registered and audited to satisfy both cybersecurity and regulatory requirements.