2020-04-28 Side channel vulnerability of ECDSA key generation

Vulnerability Description

Short Decription

The current implementation of ECC key generation allows an attacker to recover the private key.

Detailed Description

Obtaining precise timings on the comparison in the key generation enabled the attacker to learn leading bits of the ephemeral key used during ECDSA signatures and to recover the private key.

Vulnerability Severity

Impact / Implications

Exposure of the private ECC key.

Corrective Action or Resolution

Affected entities should update to Hilscher mbedtls version V1.2.0.0.

Workaround

There is no workaround.

Additional Information

Note the hilscher mbedtls version V1.2.0.0 on platforms netX51/52, netX100/500, netX4000 are affected by this vulnerability. mbedTLS version V1.2.0.0 and prior for the netX90 platform is not affected as the signature generation is directly done using the cryptographic accelerator which does inclusion of blinding scalar reduction at the end.

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-16910

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-18222

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