Описание
Generating the ECDSA nonce k samples a random number r and then truncates this randomness with a modular reduction mod n where n is the order of the elliptic curve. Meaning k = r mod n. The division used during the reduction estimates a factor q_e by dividing the upper two digits (a digit having e.g. a size of 8 byte) of r by the upper digit of n and then decrements q_e in a loop until it has the correct size. Observing the number of times q_e is decremented through a control-flow revealing side-channel reveals a bias in the most significant bits of k. Depending on the curve this is either a negligible bias or a significant bias large enough to reconstruct k with lattice reduction methods. For SECP160R1, e.g., we find a bias of 15 bits.
| Релиз | Статус | Примечание |
|---|---|---|
| devel | needs-triage | |
| esm-apps-legacy/xenial | needs-triage | |
| esm-apps/bionic | needs-triage | |
| esm-apps/focal | needs-triage | |
| esm-apps/jammy | needs-triage | |
| esm-apps/noble | needs-triage | |
| esm-apps/resolute | needs-triage | |
| esm-apps/xenial | ignored | end of ESM support, was needs-triage |
| focal | ignored | end of standard support, was needs-triage |
| jammy | needs-triage |
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EPSS
4.1 Medium
CVSS3
Связанные уязвимости
Generating the ECDSA nonce k samples a random number r and then truncates this randomness with a modular reduction mod n where n is the order of the elliptic curve. Meaning k = r mod n. The division used during the reduction estimates a factor q_e by dividing the upper two digits (a digit having e.g. a size of 8 byte) of r by the upper digit of n and then decrements q_e in a loop until it has the correct size. Observing the number of times q_e is decremented through a control-flow revealing side-channel reveals a bias in the most significant bits of k. Depending on the curve this is either a negligible bias or a significant bias large enough to reconstruct k with lattice reduction methods. For SECP160R1, e.g., we find a bias of 15 bits.
Generating the ECDSA nonce k samples a random number r and then trunc ...
Generating the ECDSA nonce k samples a random number r and then truncates this randomness with a modular reduction mod n where n is the order of the elliptic curve. Meaning k = r mod n. The division used during the reduction estimates a factor q_e by dividing the upper two digits (a digit having e.g. a size of 8 byte) of r by the upper digit of n and then decrements q_e in a loop until it has the correct size. Observing the number of times q_e is decremented through a control-flow revealing side-channel reveals a bias in the most significant bits of k. Depending on the curve this is either a negligible bias or a significant bias large enough to reconstruct k with lattice reduction methods. For SECP160R1, e.g., we find a bias of 15 bits.
Уязвимость функции wc_ecc_sign_hash() библиотеки SSL/TLS WolfSSL, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации
EPSS
4.1 Medium
CVSS3