Univention Corporate Server 4.3 erratum 64 (security)

This update addresses the following issues:
* There is an overflow bug in the AVX2 Montgomery multiplication procedure
  used in exponentiation with 1024-bit moduli. 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 DH1024 are considered just feasible, 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
  significant. However, for an attack on TLS to be meaningful, the server
  would have to share the DH1024 private key among multiple clients, which is
  no longer an option. (CVE-2017-3738)
* Because of an implementation bug the PA-RISC CRYPTO_memcmp function is
  effectively reduced to only comparing the least significant bit of each
  byte. This allows an attacker to forge messages that would be considered as
  authenticated in an amount of tries lower than that guaranteed by the
  security claims of the scheme. The module can only be compiled by the HP-UX
  assembler, so that only HP-UX PA-RISC targets are affected. (CVE-2018-0733)
* Constructed ASN.1 types with a recursive definition (such as can be found
  in PKCS7) could eventually exceed the stack given malicious input with
  excessive recursion. This could result in a Denial Of Service attack. There
  are no such structures used within SSL/TLS that come from untrusted sources
  so this is considered safe. (CVE-2018-0739)