Hardening PKI to Address the IoT and Mobile Devices

Leave a comment

Source: https://guardtime.com/blog/part-1-hardening-pki-with-ksi

PKI Primer

Public Key Infrastructure is a fairly complex set of technologies, people, policies, and procedures, which are used together to request, create, manage, store, distribute, and (ultimately) revoke digital certificates – binding public keys with an identity (such as an organization, address, personal, or email).

These certificates are the staple solution today for verifying that a public key belongs to an individual.  These technologies are used in conjunction with everything from web-based browser authentication to e-commerce and identity management for access to government and commercial e-services.

The impetus for PKI occurred in the 70s and in reality before the Internet was the Internet. Conversion of PKI schemes into successful commercial operation has been a relatively slow moving process.  In reality PKI’s progress, as an industrial identity control scheme has been slow and challenging, hampered by its complexity and vulnerabilities.

Today, binding a public key with a respective user identity occurs via a Certificate Authority (CA).  The CA is responsible for the issuance of digital certificates as a trusted third party by both the owner of the certificate and the parties relying upon the certificate.

Several trust anchors are involved to authorize the binding of public keys with user identities.  User identities are unique within each CA domain and third party Validation Authorities (VAs) can provide a validation service on behalf of the CA.  Registration Authorities (RAs), Certificate Revocation Lists (CRLs) and Online Responders (Online Certificate Status) further complicate this picture, ensuring that the validity of signatures signed with a private key cannot be legally denied by the signer (non-repudiation)[1] and  valid – that the certificate is specifically bound to an individual in a way that is legally recognized, that each certificate’s signature is valid, the current date and time are within the certificates validity period, and that the certificate(s) have not been corrupted or malformed all the way up a certificate chain to the root certificate.

PKI for M2M and IoT

Further complicating this picture, conventional PKI solutions typically require manual interaction for the certification of a public key during an identity check. While this is not a substantial issue with e-mail encryption, (the participants are natural persons), this becomes problematic with machine-to-machine (M2M) based authentication where the embedded systems are machines, which require automatic processing of certification requests.  How can any of these interactions be trusted without verification? Currently, as the only tool available for identity management, PKI as a scalable identity infrastructure has proven impractical to secure the billions of mobile devices (the Internet of Things (IoT), as well as the networks they utilize.  There has been an explosion in the number of required certificates, as each device requires it’s own unique certificate.  Moreover, many of these M2M networks are distributed and decentralized, potentially having to utilize many disparate CAs.  The framework breaks.  This liability means it is imperative to securely automate certificate provisioning, renewal, and revocation processes.

Enter Guardtime and Keyless Signature Infrastructure (KSI)

At Guardtime, we believe that in order to seriously delivery security to users using this framework, we have to understand the weakness of the tools and their components.

Guardtime and Keyless Signature Infrastructure is a significant way to strengthen PKIs weak areas without increasing costs.  With the pervasiveness of today’s threats, the Internet is now faced with a fundamentally grave situation from the multitude of attack vectors that can affect PKI security (phishing, viruses, malware, identity data losses, misconfiguration, etc).

The security community can no longer afford to blindly implement PKI technologies just because it’s the only tool in the toolbox.   PKI must be upgraded to address its scaling challenges, trust anchor, evidence portability, and administration liabilities.

What is KSI?

KSI is a technology invented by Guardtime to provide massively scalable strong data integrity, tamper evidence and backdating protection for literally any kind of digital asset. KSI provides verifiable guarantees that data has not been tampered with since it was signed.

A Guardtime signature provides proof of time, identity, and authenticity without the reliance on cryptographic keys and secrets, or trust anchors like systems administrators or Certificate Authorities.  Guardtime signatures can be verified in real-time, providing continuous integrity monitoring for literally any kind of digital asset or data object.

KSI Compliments to PKI

PKI has been tailored to enable secrecy, obfuscation and identity verification but it does require a large amount of trust be vested in one or more trust anchors; from the public Certificate Authorities to internal Certificate Management Systems and the Certificate Revocation Lists themselves.  KSI can be used to secure a PKI infrastructure and/or enhance CRLs by automating Certificate Revocation.

KSI does not require trust authorities and facilitates automated verification.  The signatures are devoid of any secret data and can be used to mathematically verify the integrity of the data, providing non-repudiation, while also protecting against backdating.

PKI vendors are developing CA suites to address the scalability and portability challenges associated with automated certificate management for large scale (such as IoT and M2M) identity management.  Guardtime can assist these PKI platform vendors to ensure the coherence and real-time resilience of their platforms, as well as strongly backstop the authenticity of identities on their ever-growing networks in a cost-effective, scalable, and compliance-related manner.

Securing Public Key Infrastructure Components with KSI

Guardtime’s Videri Gateway is the fundamental component needed to secure a complex infrastructure such as PKI.  Videri is a KSI-standards based authentication gateway (appliance) that can be used to ensure critical PKI application, credential and configuration integrity.

Videri is real-time application and integrity monitoring and validation for Public Key Infrastructure platforms.  PKI critical application, security, and static configuration components can be validated in real-time to ensure tampering and malicious attack of the infrastructure has not occurred.  Moreover, all audit and event logs associated with each PKI component become tamper evident with proveably secure and mathematically verifiable methods.  Videri integrity validation and intelligence can be exported in real-time to your Security Intelligence and Event Management (SIEM) system, or Guardtime’s GuardView SIEM for real-time alerting and dashboard management of critical PKI components, applications, subsystems, configuration files, or credentials.

KSI can be used to secure literally any kind of hierarchical CA model.  Where the CA consists of clearly defined parent/child relationships, child subordinate CAs are certified by their parent CA-issued certificates, which bind a CA’s public key to it’s identity.  Each of these relationships requires careful configuration management; planning, and the creation of operational and administrative dependencies with trust anchors that build up to the root CA .  Operational dependence on these child CAs for mission critical functions means real-time integrity monitoring is a must.  A root CA is the important point of trust in an organization and subordinate CA are created to provide administrative benefits from the root and are set up practically to separate usage, organizational division, geographic divisions, load balancing, and backup and fault tolerance.  These configurations and associated policies benefit from KSI integration.

KSI can be implemented into these systems to secure and provide real-time continuous integrity monitoring of all critical CA management applications such as Certificate Services for a particular PKI deployment.  These services include any CryptoAPIs and Cryptographic Service Provider (CSP) dependencies underlying the PKI system for cryptographic operations and private key management, as well as signing and verifying the Certificate stores themselves, which are responsible for storing and managing certificates in the enterprise.

Moreover, with the increasing use of software-based CSPs, private keys and cryptographic operations are not well isolated from the server they run on and the operating system.  With this vulnerability, application or OS tampering are common exploitation approahes to expose keys and is in fact one of PKIs most glaring fundamental vulnerabilities.  With KSI and Videri, configuration and application baselines can be monitored in real-time to ensure that software-based CSPs are secure with real-time tamper evidence of dependent applications and the OS components themselves in the event of attack.

For CA installation, KSI is implemented to sign and provide real-time validation to CA configuration files, security-related files responsible for permission management between PKI subsystems, and to ensure tamper detection of any certificate templates used by the CA and infrastructure for Certificate Services.  These include all Certificate Server services, Public Key Group policies, Issuer Statements, Certificate Database Logs and their associated configuration files (and dependencies) as well as common web enrollment applications associated with a PKI deployment.

[1] A word on liability.. It is important to consider that the Internet’s increasing reliance on PKI has in fact developed a reliance on CAs.  CA vendors have NEVER paid out in the case of fraud or stolen credentials or identities.  Looking under the hood, CAs agree that when pressed on their warranty programs, there is no substantial backing to a claim if a certificate is used maliciously.  The result:  organizations using PKI have outsourced their trust to authorities that simply have no skin in the game, nor will guarantee their security.  Where is the accountability?


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: