Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 c20d94f27b45fe21…

MALICIOUS

Office (OOXML) / .XLSX

62.1 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: 7225cc624760de8f3b269e28fc279e53 SHA-1: 3170c0575127a659ec46f75ec6ea819596c3b02c SHA-256: c20d94f27b45fe21f01e19ca687a986749ed922b69bd8f53d6a0804b86ae3838
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel file containing Excel 4.0 macros, as indicated by the OOXML_XLM_MACROSHEET heuristic. The extracted macro code contains a WMIC command that attempts to create a process executing 'C:\ProgramData\excel.rtf'. This strongly suggests the document's purpose is to download and execute a second-stage payload from that location.

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.

FilenameKindSourceSize
xlm_sheet_00.bin
14dc197c454c9b620fb47e2896fbdc9148b03770301242c5cade871f1cc55525		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 58802 bytes

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