Microsoft Excel Style Handling and Repair Remote Code Execution Vulnerability
Microsoft Excel is prone to a remote code-execution vulnerability.
Successfully exploiting this issue allows attackers to execute arbitrary code in the context of targeted users.
A proof-of-concept malicious code named 'Trojan.Hongmosa' is actively exploiting this vulnerability, which results in crashing Excel running on Simplified Chinese, Traditional Chinese, Japanese, or Korean Windows.
Note that Microsoft Office applications include functionality to embed Office files as objects contained in other Office files. As an example, Microsoft Word files may contain embedded malicious Microsoft Excel files, making Word documents another possible attack vector.
This issue is distinct from the issue described in BID 18422 (Microsoft Excel Unspecified Remote Code Execution Vulnerability). Proof-of-concept 'Nanika.xls' was originally thought to be related to BID 18422; however, reports indicate that 'Nanika.xls' triggers this vulnerability.