Office (OOXML) / .XLSX malware analysis — malicious · ad882513481c0d33

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 4e26ccd9dc93f0b857ccf2994ac499ac SHA-1: 89f4ecb9595b0c4b371a842e922c212e202c123f SHA-256: ad882513481c0d3356fa8a46a8136c62fe9ec3383b2eb0df0d403a425c363988

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The sample is an Excel file containing Excel 4.0 macros, a known technique for initial execution. The macro executes a command using 'wmic process call create' to run a file named 'excel.rtf' from the ProgramData directory. This suggests the macro's purpose is to download and execute a second-stage payload from a remote location, although the specific payload and its origin are not detailed in 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` `2d31fa72449e448b9ea0a936d46e19a891cd90dc8dc4cfef5827e99b5d94622b`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	74576 bytes

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