MS Office Excel (all versions) Arbitrary Code Execution Vulnerability
MS Excel contains a remote code execution vulnerability upon processing OLE objects. Although this is a different issue from the MS Word HTA execution vulnerability, it has been patched together, 'silently'. By performing some tests from the Word HTA PoC posted on exploit-db[dot]com, it´s possible to exploit it through Excel too, however the target would need to either accept a security warning regarding external links or double click inside the Excel window, same applies for Powerpoint, so I guess this is the reason, Word caught the attention and no exploit PoC was made available to other Office apps. This vulnerability exists in the way Excel handles parameters passed to the "DDEService" attribute of links, leading to the search for a program to display it. As it does not impose restrictions on what program is going to be executed, for instance, only programs located in the Office install directory, it is possible to invoke arbitrary local programs with parameters, leading to system compromise. Since Excel blocks automatic update of linked files, the target must be tricked into double clicking anywhere inside the document.
