What Is A Self Signed Certificate: Their Benefits And Risks

Understanding what is a self signed certificate and whether you should use one can make a huge difference to your website’s security. A self signed SSL certificate, in simple terms, is an SSL (Secure Sockets Layer) certificate that you generate and sign yourself, meaning no third-party Certificate Authority vouches for its authenticity. This approach has both benefits and risks regarding securing data and personal information. In this comprehensive guide, we explain what self signed certificates are, their pros and cons, and when (and if) it’s a good idea to use one for your online business.

KEY TAKEAWAYS

• A self signed certificate provides encryption but isn’t verifiable or trusted by browsers because a CA does not sign it.
• CA-issued SSL certificates provide better security, trust, and compliance compared to self signed versions, making them essential for any public-facing website.
• Self signed ssl certificates are fast, free, and flexible, but are best suited for non-public or internal sites.
• Although encrypted, self signed certificates lack trust, revocation, visibility, and compliance, posing serious security risks if used on a public-facing website.
• To securely use self signed certificates, implement layered security controls like MFA, HSMs, and continuous monitoring.

What is a Self Signed Certificate?

A self signed certificate is a type of public key certificate, similar to a standard SSL certificate. Its main function is to enable secure communication between a web browser and the server hosting your website. It also verifies the identity of the site’s domain name and ensures it is legitimate.

Traditionally, for a website to be trusted by web browsers and search engines, its SSL/TLS certificate must be issued and signed by a Certificate Authority (CA). CAs are trusted third parties that verify the identity of the certificate requester before issuing a certificate. When a browser connects to a website, it checks whether a CA signed the site’s digital certificate. If a CA signed it, the browser trusts the certificate. It establishes a secure connection, making it essential to website security.

This is where self signed certificates diverge in that you generate and sign them yourself, without a third-party CA. However, it is technically an SSL certificate, as it provides encryption and confirms the identity of a website. But, the difference is that it isn’t “vouched for” by a trusted CA. This is where things get a little problematic. Because a CA hasn’t verified the identity of the domain associated with the site or signed it digitally, browsers do not inherently trust self signed certificates.

How Self Signed SSL Certificates Work

Self signed SSL certificates operate on the same cryptographic principles (public-key infrastructure) as CA-signed certificates and contain all the components you’d expect:

• A public key.
• The certificate holder’s identity.
• Issue and expiry dates.
• A digital signature.

The above-mentioned digital signature is generated using a private key that corresponds to the public key in the same certificate; hence, it’s called “self signed.”

When a web browser connects to a server using a self signed certificate, the SSL/TLS handshake proceeds as usual. The server presents its certificate, and the browser tries to verify its authenticity. This is where things go sideways, because the certificate hasn’t been signed by a recognized and trusted CA, so the client can’t establish a chain of trust back to a root certificate it inherently trusts. This inability to verify the certificate’s authenticity triggers the browser warnings visitors find when they attempt to access a site without a CA-issued SSL certificate installed. To proceed with the connection, they must ignore these warnings and connect at their own risk.

Self Signed Certificates vs CA-Issued SSL Certificates

The major difference between self signed and CA certificates is the level of third-party validation and the automatic trust. Public CA certificates undergo verification of the requester’s identity before being issued. This can range from domain validation to extensive organizational validation, depending on the type of SSL certificate.

CAs are organizations that are audited and globally accepted by browsers and operating systems. The certificate’s signature is checked so it can be traced back to a trusted root CA in its pre-installed trust store. This process establishes a chain of trust that confirms:

• The website is who it claims to be.
• The communication channel is encrypted and secure.
• The data has not been tampered with during transfer.

Both start the validation process by generating a Certificate Signing Request (CSR), a block of encoded text that contains the public key and identification details (domain name, organization, and location). A CA uses this CSR to verify the identity of the requester before issuing a trusted certificate.

This can range from domain validation to extensive organization validation, depending on the certificate type. In the case of self signed certificates, the certificate owners sign the CSR themselves, bypassing the external validation. This makes them easy to create and deploy, but managing them tends to be more complex and prone to errors, such as failing a security review. CA-signed certificates, on the other hand, can be more involved initially, but they benefit from automation that simplifies issuance and renewal.

They also differ in cost. Generating self signed certificates is free, whereas CA-signed versions may incur fees, including the costs of purchasing new certificates and renewals. When you sign up for Web or WordPress Hosting with Hosted.com, we include a free SSL certificate, signed off and verified by a trusted CA.

When to Use Self Signed Certificates

People use self signed certificates for several reasons, mainly in controlled or internal use environments.

Firstly, as we mentioned, generating a self signed certificate is always free. A CA-issued certificate, especially with higher validation levels, can range from free to hundreds or thousands of dollars annually, making them cost-effective only until you have a site ready to be published.

You can generate your server certificate almost instantly using tools like OpenSSL req without needing to go through CSR generation, validation, and issuance. This is great for development and testing.

Developers can test SSL/TLS functionality and quickly set up HTTPS (Hypertext Transfer Protocol Secure) connections on their local machines or test servers to simulate an encrypted connection for a live website.

For sites that are only used in a company’s internal network (intranets) and aren’t exposed to the public internet, self signed certificates can be used since they aren’t accessible externally; therefore, CA validation isn’t required.

This enables them to provide security by establishing their own trust relationships and distribution methods, creating secure communication channels tailored to their specific environment and requirements.

The Risks of Using a Self-Signed Certificate

While both use the same public-key cryptography for encryption, there’s no independent verification of the web server’s identity during the issuance process, because the self signed version is signed by the same entity it identifies. This poses some major security risks for public-facing websites, including:

The most common risk is browser warnings like the Authentication Failed error. Web browsers don’t automatically trust self signed certificates, leading to security warnings that tell visitors the site isn’t safe. This can damage trust and credibility and increase bounce rates, as visitors will generally leave before accessing an unsecured website. It also hurts SEO (Search Engine Optimization), as having an SSL is a major ranking factor.

Also, without publicly trusted Certificate Authority validation, it’s easier for malicious actors to create fake websites using self signed certificates that appear legitimate, making phishing attacks more effective.

Man-in-the-Middle (MITM) attacks are the most crucial security issues to consider. In an MITM attack, the communication between a browser and a server is intercepted. If a legitimate server uses a self-signed SSL certificate, an attacker can relatively easily create their specific self signed certificate or duplicate the legitimate one if it’s not properly secured.

As the browser is already expecting a certificate that a CA doesn’t trust, the user may bypass the warning, unknowingly establishing a secure connection with the attacker instead of the legitimate server. The encryption exists, but it’s between the client and the attacker, not the client and the server.

If the private key of a self signed certificate is stolen or expires, there is no centralized mechanism (such as a Certificate Revocation List or Online Certificate Status Protocol, or OCSP) to revoke it or inform browsers that the compromised certificate should not be trusted.

Unlike CAs, which adhere to industry standards for key strength and algorithms, self-signed certificates can be generated with weaker security protocols if not done carefully, thereby increasing vulnerability to attacks.

Lastly, only CA-issued certificates comply with data protection regulations, such as PCI-DSS, HIPAA, and GDPR. This means that if sensitive data is exposed due to security vulnerabilities, companies may face fines and legal action.

Best Practices for Self Signed Certificates

If using self-signed SSL certificates (remember, they’re not a good idea for external sites), following best practices can keep your internal systems secure and prevent unauthorized access.

Implement multi-factor authentication and single sign-on as security measures, especially for admin access and certificate management. These authentication layers provide additional protection even if certificates are compromised.

Monitor for security vulnerabilities and compromised certificates through regular security assessments, log analysis, and threat intelligence feeds. Enable automated monitoring systems that can detect unusual usage patterns, expired certificates, or potential security issues.

Use Hardware Security Modules (HSMs) to safeguard sensitive data, like private keys and configuration files. HSMs provide tamper-proof hardware protection, reducing the risk of private key compromise compared to software-based storage methods.

Lastly, ensure they are properly added to and managed in trusted root certificate stores across systems or browsers, with regular audits.

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– What Is SSL Certificate Management And How To Implement It

– Free SSL Vs Paid SSL Certificates, Which Provides Better Value

– What Is Website Security? 10 Best Practices To Protecting Your Site From Hackers

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