Affected: OpenSSL

Normally in OpenSSL EC groups always have a co-factor present and this is used in side channel resistant code paths. However, in some cases, it is possible to construct a group using explicit parameters (instead of using a named curve). In those cases it is possible that such a group does not have the cofactor present. This can occur even where all the parameters match a known named curve. If such a curve is used then OpenSSL falls back to non-side channel resistant code paths which may result in full key recovery during an ECDSA signature operation. In order to be vulnerable an attacker would have to have the ability to time the creation of a large number of signatures where explicit parameters with no co-factor present are in use by an application using libcrypto. For the avoidance of doubt libssl is not vulnerable because explicit parameters are never used. Fixed in OpenSSL 1.1.1d (Affected 1.1.1-1.1.1c). Fixed in OpenSSL 1.1.0l (Affected 1.1.0-1.1.0k). Fixed in OpenSSL 1.0.2t (Affected 1.0.2-1.0.2s).

Affected: Ubuntu:16.04:LTS: openssl, Ubuntu:18.04:LTS: openssl

Cesar Pereida García, Sohaib ul Hassan, Nicola Tuveri, Iaroslav Gridin, Alejandro Cabrera Aldaya, and Billy Brumley discovered that OpenSSL incorrectly handled ECDSA signatures. An attacker could possibly use this issue to perform a timing side-channel attack and recover private ECDSA keys. (CVE-2019-1547)

Matt Caswell discovered that OpenSSL incorrectly handled the random number generator (RNG). This may result in applications that use the fork() system call sharing the same RNG state between the parent and the child, contrary to expectations. This issue only affected Ubuntu 18.04 LTS and Ubuntu 19.10. (CVE-2019-1549)

Guido Vranken discovered that OpenSSL incorrectly performed the x86_64 Montgomery squaring procedure. While unlikely, a remote attacker could possibly use this issue to recover private keys. (CVE-2019-1551)

Bernd Edlinger discovered that OpenSSL incorrectly handled certain decryption functions. In certain scenarios, a remote attacker could possibly use this issue to perform a padding oracle attack and decrypt traffic. (CVE-2019-1563)