There is a carry propagating bug in the Broadwell-specific Montgomery multiplication procedure in OpenSSL 1.0.2 and 1.1.0 before 1.1.0c that handles input lengths divisible by, but longer than 256 bits. Analysis suggests that attacks against RSA, DSA and DH private keys are impossible. This is because the subroutine in question is not used in operations with the private key itself and an input of the attacker's direct choice. Otherwise the bug can manifest itself as transient authentication and key negotiation failures or reproducible erroneous outcome of public-key operations with specially crafted input. Among EC algorithms only Brainpool P-512 curves are affected and one presumably can attack ECDH key negotiation. Impact was not analyzed in detail, because pre-requisites for attack are considered unlikely. Namely multiple clients have to choose the curve in question and the server has to share the private key among them, neither of which is default behaviour. Even then only clients that chose the curve will be affected.

Affected: Ubuntu:14.04:LTS: openssl, Ubuntu:16.04:LTS: openssl

Guido Vranken discovered that OpenSSL used undefined behaviour when performing pointer arithmetic. A remote attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. This issue only applied to Ubuntu 12.04 LTS and Ubuntu 14.04 LTS as other releases were fixed in a previous security update. (CVE-2016-2177)

It was discovered that OpenSSL did not properly handle Montgomery multiplication, resulting in incorrect results leading to transient failures. This issue only applied to Ubuntu 16.04 LTS, and Ubuntu 16.10. (CVE-2016-7055)

It was discovered that OpenSSL did not properly use constant-time operations when performing ECDSA P-256 signing. A remote attacker could possibly use this issue to perform a timing attack and recover private ECDSA keys. This issue only applied to Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2016-7056)

Shi Lei discovered that OpenSSL incorrectly handled certain warning alerts. A remote attacker could possibly use this issue to cause OpenSSL to stop responding, resulting in a denial of service. (CVE-2016-8610)

Robert Święcki discovered that OpenSSL incorrectly handled certain truncated packets. A remote attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. (CVE-2017-3731)

It was 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. This issue on…