Office (OOXML) / .XLSX malware analysis — malicious · 966ad635982ceefe

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 1c0dd1f4874e1fb1f3840bd64909bd8b SHA-1: 0c8db0242586bcf1a17b73c29869119653e9701a SHA-256: 966ad635982ceefec4d78ddb8df3d5c29879ac652f37f1d060f5d2133f1b01a3

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Service Execution: Service Execution

The sample is an Excel file containing Excel 4.0 macros, as indicated by the 'OOXML_XLM_MACROSHEET' heuristic. The extracted macro content reveals a command to execute 'mshta' with a specific file path 'C:\ProgramData\excel.rtf', suggesting an attempt to download and execute a second-stage payload. This is a common technique for initial execution.

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` `abb41a7c12181de7efb4a1a2f51d0dff174cb5c60f7ab54b02b8f84a25ca60ed`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	64105 bytes

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