Factorization Flaw in TPM Chips Makes Attacks on RSA Private Keys Feasible

A flawed Infineon Technology chipset used on PC motherboards to securely store passwords, certificates and encryption keys risks undermining the security of government and corporate computers protected by RSA encryption keys. In a nutshell, the bug makes it possible for an attacker to calculate a private key just by having a target’s public key.

Security experts say the bug has been present since 2012 and found specifically in the Infineon’s Trusted Platform Module used on a large number of business-class HP, Lenovo and Fijitsu computers, Google Chromebooks as well as routers and IoT devices.

The vulnerability allows for a remote attacker to compute an RSA private key from the value of a public key. The private key can then be misused for purposes of impersonation of a legitimate owner, decryption of sensitive messages, forgery of signatures (such as for software releases) and other related attacks, according to researchers.

The Infineon flaw is tied to a faulty design of Infineon’s Trusted Platform Module (TPM), a dedicated microcontroller designed to secure hardware by integrating cryptographic keys into devices and used for secured crypto processes.

Security researchers, at Masaryk University in Brno, Czech Republic, who discovered the vulnerability (CVE-2017-15361) earlier this year, said the flaw occurs during the generation of RSA keys used by a software library in cryptographic smart cards, security tokens and other secure hardware chips manufactured by Infineon.

“The currently confirmed number of vulnerable keys found is about 760,000 but possibly up to two to three magnitudes more are vulnerable,” according to researchers who published a technical analysis of the bug on Monday.

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Source: ThreatPost