Pierluigi Paganini February 14, 2012

After the attacks against certification authorities such as VeriSign, Comodo and DigiNotar the level of confidence in the model based on certificates is in sharp decline. There is widespread accusations addressed to the PKI paradigm (public key infrastructure ) which is based on the concept to request to trusted and credited third parties to guarantee on the identity of an entity in the digital world.
On more than one occasion have been identified vulnerabilities to the model and were shown the dangers arising from impairment of such architectures, the risks that pose a serious threat from private sector to the government one. Unfortunately, the criticism of the model are not moved for technical reasons, we are faced with an impressive business, the monetization of our digital identity.

The news that we are going to discuss is undoubtedly disconcerting and raises serious doubts about the trustworthiness of the trusted “third party”, main components of the PKI model. Digital Certificate Authority (CA) Trustwave revealed that it has issued a digital certificate that enabled an unnamed private company to spy on SSL protected connections within its corporate network. The news has literally shocked the Mozilla community that has immediately requested to remove the CA’s root certificate from Firefox.

The certificate issued by Trustwave is recognized as a subordinate root and enabled to sign digital certificates for virtually any domain on the Internet. Trustwave has decided to make a public declaration on the event to reassure their customers. According the declaration of the company it has been updated their legal repository (https://ssl.trustwave.com/CA). It has been  revoked subordinate root.

This single certificate was issued for an internal corporate network customer and not to a ‘government’, ‘ISP’ or to ‘law enforcement’. It was to be used within a private network within a data loss prevention (DLP) system. The subordinate certificate was subject to a Certification Practice Statement (CPS), Subscriber Agreement and Relying Party Agreement crafted by Trustwave after an audit of the customer physical security, network security, and security policies.
The system was created using dedicated hardware device designed for SSL proxy and acceleration, with a FIPS-140-2 Level 3 compliant Hardware Security Module (HSM) (http://en.wikipedia.org/wiki/Hardware_security_module) for subordinate root storage and for the purpose of private key generation of the re-signed SSL certificates. This means that once the trusted subordinate root was placed into the device it could not be extracted.

The statement remarks two main aspects:

• the subordinate root could not be stolen or abused because it was stored in a HMS (Hardware Security Module) device used for the management of digital keys. It’s usage guarantees that it’s impossible to estract the keys from the device.  These modules are physical devices that traditionally come in the form of a plug-in card or an external TCP/IP security device, their goals are:
  • onboard secure generation
  • onboard secure storage
  • use of cryptographic and sensitive data material
  • offloading application servers for complete asymmetric and symmetric cryptography.

  HSMs provide both logical and physical protection of these materials from non-authorized use and potential adversaries.  Trustwave declared that the issuing of subordinate roots to private companies has been done with the purpose to allow inspection of the SSL-encrypted traffic that passes through their networks. Anyway the CA decided to stop issuing this type of certificates in the future, revoking the existent ones.

• the company has performed physical security audits to make sure that the system can’t be used to intercept SSL-encrypted (Secure Sockets Layer-encrypted) traffic on different network.