Providing and managing privileged remote access to servers and systems is critical for uninterrupted operations in modern-day business. Secure Shell (SSH) is a standard network protocol used for this purpose. SSH keys (a cryptographic key pair) remain the most widely used approach for SSH authentication.
As organizations grow and their infrastructures expand, the need for SSH access to an increasing number of systems and devices also rises, leading to a surge in the number of SSH keys. While SSH keys offer a more secure and convenient alternative to passwords, poor key management practices can lead to uncontrolled proliferation and distribution of these keys across the organization. This is known as SSH key sprawl. As SSH keys often grant root-level access to systems, key sprawl can complicate access management and highly increase the risk of security breaches.
What Causes SSH Key Sprawl?
- Ad-hoc Key Generation: As SSH keys can be generated relatively quickly and easily with no expiration, users tend to create keys on the fly for various purposes, leading to a large pool of unmanaged keys. Further, due to weak policy enforcement, different teams or departments might adopt varying practices for generating and managing SSH keys, resulting in inconsistency and key sprawl.
- Lack of Centralized Key Management: Unlike SSL/TLS certificates, SSH keys do not have an expiration date. The ad-hoc key generation, coupled with the fact that keys don’t expire, leads to the accumulation of many dormant and forgotten SSH keys. Without a centralized management system, it is challenging for security teams to maintain visibility and track which keys are in use, where they are used, and who controls them. As a result, a high volume of keys are left unmanaged for years, resulting in static, stale, and stray keys.
- Poor Key Rotation Practices: Regularly rotating SSH keys is a security best practice. However, due to the lack of visibility into their dependencies and configurations and manual processes, administrators often struggle to rotate keys regularly and delete inactive keys when employees leave the company or change roles.
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The Risks of SSH Key Sprawl
1. Unauthorized Access and Data Breaches:
- Proliferation of keys: With a large number of keys in play, it becomes challenging to monitor access privileges and ensure that each key is regularly rotated and properly managed. This increases the likelihood of unauthorized access to critical systems.
- Stale Keys: As SSH keys never expire, they continue to provide access to business-critical systems and applications unless explicitly removed. As an example, SSH keys of former employees often remain active due to the lack of a systematic revocation process. This can be exploited by disgruntled ex-employees or malicious actors to gain unauthorized access.
- Shared Keys: Another security risk emerges from shared keys. Often, SSH keys are shared among multiple users and reused across different systems, increasing the risk of compromise.
- Weak Keys: The security of SSH connections depends upon the strength of SSH keys. When keys are created with weak key algorithms and bit lengths, they can be exploited to gain unauthorized access to critical systems.
- Poor Key Distribution Methods: Keys distributed via insecure methods, such as email and shared drives, are vulnerable to interception, allowing attackers to use these keys to access critical systems.
2. Operational Complexity
- Management Overhead: Tracking and managing a high volume of SSH keys can be cumbersome and resource-intensive, diverting focus from other critical tasks. Tasks such as key distribution, rotation, and revocation are a significant challenge when performed manually and increase the likelihood of errors and oversight.
- Difficulties in User Onboarding/Offboarding
- Onboarding: As new employees join, ensuring they receive the appropriate access without delay is challenging in an environment with a large number of SSH keys. Lack of centralized key management can result in either delayed access or overly broad access privileges.
- Offboarding: Revoking employees’ SSH keys when they leave is crucial. In a sprawl situation, it’s easy to miss some keys, leaving access points open and increasing security risks.
- Delayed Incident Response: In the event of a security incident, quickly identifying and revoking compromised keys is critical. SSH key sprawl complicates this process. Lack of a clear understanding of key distribution and access permissions delays response time and potentially increases the damage.
3. Compliance and Regulatory Challenges
- Non-Compliance: Many industries have strict regulations regarding access control and data protection, such as GDPR, HIPAA, PCI-DSS and others. Failure to manage SSH keys properly due to the absence of centralized key management can result in a weakness in controls and non-compliance with these regulations.
- Audit Failures: Performing security audits becomes more complex with an uncontrolled proliferation of keys. Auditors look for controlled and documented access mechanisms, which unmanaged SSH keys violate. This can lead to penalties, fines, or other regulatory actions.
- Legal Liability: Data breaches due to poor SSH key management can lead to lawsuits and legal liability, especially if sensitive customer, personal identifiable information (PII), and financial data is compromised.
As organizations increasingly rely on SSH for secure access to their critical systems, the potential risks associated with SSH key sprawl become more pronounced. Effective SSH key management not only safeguards against unauthorized access and data breaches but also ensures compliance with industry regulations and standards. By implementing centralized management solutions, automating key lifecycles, and enforcing rigorous policies, organizations can significantly reduce their exposure to security vulnerabilities. This proactive approach to SSH key management is essential for maintaining the integrity and security of IT infrastructures and fostering a more secure remote work environment.
To learn more about achieving complete visibility, end-to-end automation, and continuous control of your SSH Infrastructure, visit AppViewX AVX SSH Control or talk to an Expert.
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About the Author
Krupa Patil
Product Marketing Manager
A content creator focused on providing readers and prospective buyers with accurate, useful, and latest product information to help them make better informed decisions.
