Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing.

Impact summary: An attacker able to measure signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key.

CWE: CWE-208: Observable Timing Discrepancy

Description: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce.

The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1.

Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue.

The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected.

FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.

Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing.

Impact summary: An attacker able to measure signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key.

CWE: CWE-208: Observable Timing Discrepancy

Description: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce.

The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1.

Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue.

The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected.

FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.

openssl: openssl: Denial of Service via excessive memory allocation in CRL distribution point processing openssl: openssl: Traffic amplification Denial of Service via QUIC packet over-accounting openssl: openssl: Denial of Service via inefficient QUIC stream reassembly openssl: OpenSSL: Private key recovery via timing side-channel in generic elliptic curve operations openssl: openssl: Denial of Service via excessive QUIC packet buffer retention openssl: openssl: information disclosure via non-constant-time SM2 scalar multiplication on ARM64 and RISC-V openssl: openssl: Denial of Service via out-of-bounds write during TLS context switch openssl: OpenSSL: Denial of Service via unenforced QUIC connection flow control openssl: openssl: Denial of Service via crafted CMP certificate revocation response openssl: OpenSSL: Denial of Service via undersized DTLS record openssl: OpenSSL: Private key recovery via SM2 timing side-channel openssl: compat-openssl: openssl: Information disclosure via DTLS handshake retransmission openssl: OpenSSL: Denial of Service via unbounded QUIC connection identifier backlog

Affected: Ubuntu:Pro:14.04:LTS: openssl, Ubuntu:Pro:16.04:LTS: openssl, Ubuntu:Pro:16.04:LTS: edk2, Ubuntu:Pro:16.04:LTS: nodejs, Ubuntu:Pro:FIPS:16.04:LTS: openssl, Ubuntu:Pro:18.04:LTS: openssl, Ubuntu:Pro:18.04:LTS: openssl1.0, Ubuntu:Pro:18.04:LTS: edk2, Ubuntu:Pro:18.04:LTS: nodejs, Ubuntu:Pro:FIPS-updates:18.04:LTS: openssl and 18 more

Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing. Impact summary: An attacker able to measure signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce. The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1. Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue. The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected. FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.