An issue exists in Arm Mbed TLS prior to 2.16.6 and 2.7.x prior to 2.7.15. An attacker that can get precise enough side-channel measurements can recover the long-term ECDSA private key by (1) reconstructing the projective coordinate of the result of scalar multiplication by exploiting side channels in the conversion to affine coordinates; (2) using an attack described by Naccache, Smart, and Stern in 2003 to recover a few bits of the ephemeral scalar from those projective coordinates via several measurements; and (3) using a lattice attack to get from there to the long-term ECDSA private key used for the signatures. Typically an attacker would have sufficient access when attacking an SGX enclave and controlling the untrusted OS.
| Vulnerable Product | Search on Vulmon | Subscribe to Product |
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arm mbed tls |
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fedoraproject fedora 31 |
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fedoraproject fedora 32 |
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debian debian linux 10.0 |
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