Protecting your sensitive data and other critical assets requires establishing secure access to them in the first place. Lots of organizations do this by protecting their remote servers and corporate systems with SSH keys. However, even SSH keys can be compromised and abused by malicious actors.
SSH key authentication management basics
What is SSH key management?
Secure Socket Shell (SSH) key authentication is a convenient and secure way to connect computers over the internet. It allows employees (mostly admins) to remotely access another computer, server, or network without continually logging in using a username and password. With SSH, authorized users can manage applications, execute commands, and move files from one computer to another in a fast and secure manner.
Organizations benefit a lot from using SSH key security authentication, since it secures access to servers and encrypts traffic that’s in transit between a client and a server. To connect to a remote machine, users have to generate a pair of digital keys:
- A public key that can be shared with others
- A private (or identity) key that should be kept secret by the authorized person
A simplified view of the SSH authentication process
You can ensure proper protection of keys with SSH key management — a combination of practices, policies, and tools for establishing secure SSH key usage routines within an organization. SSH key management can significantly enhance corporate cybersecurity by protecting networks and systems from both external and insider attacks. It can also help an organization comply with cybersecurity standards, laws, and regulations.
At its core, SSH key management consists of four main tasks:
- Properly provisioning SSH keys
- Keeping track of an organization’s public and private keys
- Monitoring SSH key use
- Protecting pairs of SSH keys
To accomplish these goals, system administrators apply various methods to generate, store, use, rotate, revoke, and terminate keys in a way that protects them from unauthorized users and cybercriminals.
The importance of efficient SSH key management
What happens if you fail to control your digital keys?
Since SSH keys provide access to sensitive resources and data, you should prevent them from falling into the wrong hands. Also, various laws, regulations, and standards like HIPAA, the GDPR, and PCI DSS contain specific requirements for secrets management, and SSH keys are a type of secret.
Without centralized control, you can’t know how many SSH key pairs are in your organization’s network, who uses them, and how. And if you mismanage your SSH keys, it will create severe cybersecurity risks:
1. Uncontrolled access to keys. Malicious actors can abuse unprotected SSH keys to gain access to privileged accounts. Here are a few scenarios of how this may happen:
- If users can create their own authorized SSH keys, malicious insiders may use this opportunity to generate backdoor keys.
- If an organization doesn’t monitor and rotate SSH keys, terminated employees can still access sensitive data long after they leave a position or a company.
2. Loss of keys. An important detail about SSH keys is that they are static, meaning they don’t have an expiration date. Combine this with a lack of proper secret monitoring routines and you are likely to end up with a number of legitimate SSH keys that have been misplaced or simply forgotten. Keys that are no longer actively used and the location of whose corresponding public or private key is unknown are called orphaned keys.
The longer keys are in existence, the harder it becomes for security teams to identify their purpose and to rotate them to maintain security. Also, if there are no requirements for key management and inventory procedures, you may lose access to public key storage when you’re patching, upgrading, reusing, or reinstalling servers.
3. Exposed keys. Without clear SSH key management rules, there’s always a risk of key exposure. SSH keys can be exposed either through misplacement or through unauthorized sharing.
For example, administrators can embed static SSH keys into an application’s code or scripts, making the application vulnerable to hacker attacks. Or your employees might share keys with each other using messengers and other insecure channels.
4. Duplicate keys. Without strict policies for generating SSH keys, admins may often replicate keys to share access to servers and infrastructure components among a group of employees. Duplicate keys share the same key fingerprint (a special checksum generated based on the public SSH key).
Duplicating keys significantly complicates the process of rotating a single key or revoking it without breaking other SSH key relationships. Also, availability of duplicate keys may increase the chances of malicious insiders gaining access to and misusing those keys.
All of the risks mentioned above may lead to a situation where an attacker can gain access to digital keys and use them to misuse sensitive data, install malware on corporate servers, and alter the configurations of an organization’s systems.
To avoid these cybersecurity issues, you need to enhance your SSH key management. Doing so will help you:
- Account for all generated SSH keys
- Ensure that no extra keys are generated except for valid reasons
- Know who accesses keys and when
- Avoid reusing keys across systems and users
- Immediately change or revoke access to keys
Source : ekransystem.com
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