| Description: | There is a carry propagating bug in the x86_64 Montgomery squaring
procedure in OpenSSL 1.0.2 before 1.0.2k and 1.1.0 before 1.1.0d. No
EC algorithms are affected. Analysis suggests that attacks against RSA
and DSA as a result of this defect would be very difficult to perform
and are not believed likely. Attacks against DH are considered just
feasible (although very difficult) because most of the work necessary
to deduce information about a private key may be performed offline.
The amount of resources required for such an attack would be very
significant and likely only accessible to a limited number of
attackers. An attacker would additionally need online access to an
unpatched system using the target private key in a scenario with
persistent DH parameters and a private key that is shared between
multiple clients. For example this can occur by default in OpenSSL DHE
based SSL/TLS ciphersuites. Note: This issue is very similar to
CVE-2015-3193 but must be treated as a separate problem.
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