Microsoft CVE-2017-0020:
                                                                                    Microsoft Office Memory Corruption
                                                                                    Vulnerability
                                                                            A remote
                                                                                    code execution vulnerability exists
                                                                                    in Exploit Excel Microsoft Office
                                                                                    software when the software fails to
                                                                                    properly handle objects in memory.
                                                                                    An attacker who successfully
                                                                                    exploited the vulnerability could
                                                                                    run arbitrary code in the context of
                                                                                    the current user. If the current
                                                                                    user is logged on with
                                                                                    administrative user rights, an
                                                                                    attacker could take control of the
                                                                                    affected system. 
                                                                            An
                                                                                    attacker could then install
                                                                                    programs; view, change, or delete
                                                                                    data; or create new accounts with
                                                                                    full user rights. Users whose
                                                                                    accounts are configured to have
                                                                                    fewer user rights on the system
                                                                                    could be less impacted than users
                                                                                    who operate with administrative user
                                                                                    rights. Exploitation of the
                                                                                    vulnerability requires that a user
                                                                                    open a specially crafted file with
                                                                                    an affected version of Excel Exploit
                                                                                    Microsoft Office software. In an
                                                                                    email attack scenario, an attacker
                                                                                    could exploit the vulnerability by
                                                                                    sending the specially crafted file
                                                                                    to the user and convincing the user
                                                                                    to open the file. 
                                                                            In a
                                                                                    web-based attack scenario, an
                                                                                    attacker could host a website (or
                                                                                    leverage a compromised website that
                                                                                    accepts or hosts user-provided
                                                                                    content) that contains a specially
                                                                                    crafted file designed to exploit the
                                                                                    vulnerability. An attacker would
                                                                                    have no way to force users to visit
                                                                                    the website. Instead, an attacker
                                                                                    would have to convince users to
                                                                                    click a link, typically by way of an
                                                                                    enticement in an email or instant
                                                                                    message, and then convince them to
                                                                                    open the specially crafted file.Note
                                                                                    that the Preview Pane is not an
                                                                                    attack vector for this
                                                                                    vulnerability. The security update
                                                                                    addresses the vulnerability by
                                                                                    correcting how Excel Exploit Office
                                                                                    handles objects in memory.