Office (OOXML) / .XLSX malware analysis — malicious · 95ad01f767b60c2d

MALICIOUS

Office (OOXML) / .XLSX

104.0 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000

MD5: dac2a8cf85f8e5d3577a37100593ac41 SHA-1: 7a32873b49b31ec13cb0758630301e1fa9e2ec57 SHA-256: 95ad01f767b60c2d0c633ab33ecf38237dacb9b48b2dd3b50a8a244f61e9d2c1

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The file is an Excel 4.0 macro sheet, as indicated by the OOXML_XLM_MACROSHEET heuristic. The embedded macro sheet contains obfuscated strings that appear to construct a path to a file named 'excel.rtf' within the 'C:\ProgramData\' directory. This suggests the macro is intended to execute a malicious file from this location, likely as a downloader for a second-stage payload. The exact execution mechanism and final payload are not discernible from the provided evidence.

Heuristics 1

Excel 4.0 macro sheet (1 sheet(s)) critical OOXML_XLM_MACROSHEET

Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `4f482df52accef10cbc53f9d70e34c00ae8bf43878ebda1436a58b32e76af48c`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	251020 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.