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

Static analysis result for SHA-256 8cae1536557cbe1e…

MALICIOUS

Office (OOXML) / .XLSX

86.1 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: 9f20ef5ca2ff0d9476337784dd582cd3 SHA-1: 6769428282990728b3de3036256c603dc77dfc23 SHA-256: 8cae1536557cbe1e9d074a5685e7d5e9dc24adc0eb1b80efc162eef352a3d2cf
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The critical heuristic 'OOXML_XLM_MACROSHEET' indicates the presence of an Excel 4.0 macro sheet. While the macro content is heavily truncated and obfuscated, this type of macro is commonly used to execute arbitrary commands or download and run further stages of a malicious payload. The exact commands or URLs are not discernible from the provided excerpt.

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
998c6b01a8a4cd118da8a133da5362e18ae300dc300662fdbad0ab81fa8b9bfd		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 7119 bytes

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