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

Static analysis result for SHA-256 f0f2b7db2be978f2…

MALICIOUS

Office (OOXML) / .XLSM

37.9 KB Created: 2021-02-16 07:58:10 UTC Authoring application: Microsoft Excel 16.0300
MD5: dde385f9537194c47896eb19b30fcff3 SHA-1: e1b6f5b99166ec1d09312f5e8c06e576c5113b8d SHA-256: f0f2b7db2be978f23b82879787da48278771d2c5d3540c5085f625590501bc83
130 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an XLSM document containing VBA macros, specifically an Auto_Open macro and an Excel 4.0 macro sheet. The presence of these macros, along with a hidden worksheet, strongly suggests malicious intent. The VBA code appears to be obfuscated, but the Excel 4.0 macro sheet is a known technique for executing arbitrary code. While no direct download URLs or execution commands were explicitly reconstructed from the provided snippets, the overall structure and heuristic firings indicate a downloader or initial execution stage.

Heuristics 5

  • 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.
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • VBA project inside OOXML medium OOXML_VBA
    Document contains vbaProject.bin — VBA macros present
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 2 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
9b08cd3e36715fd2a886e82f925adffcff4add9882130c80fd62265aa21725e6		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2430 bytes
vbaProject_00.bin
c4f8ae4ff1e3ceb259b814139f96b9f0cbfc0c7bbb07e08bf82c5631d42b5ada		 vba-project OOXML VBA project: xl/vbaProject.bin 22528 bytes
xlm_sheet_00.xml
01ef82e292028ae09335324928adee74336c5388e8169fdf1abc7c61814d251b		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 885 bytes

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