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

Static analysis result for SHA-256 6b9cdf009660c9ab…

MALICIOUS

Office (OOXML) / .XLSM

37.6 KB Created: 2021-04-07 07:02:41 UTC Authoring application: Microsoft Excel 16.0300
MD5: 38eee9f09cc38dad8af2cff7e9be0db2 SHA-1: dfbbb9896e9cbc991535bd1e9ba07d96a84ac91a SHA-256: 6b9cdf009660c9ab215eb52d1dbea87d67f0f5fd913c857247f696e5227d02b9
90 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is an XLSM document containing Excel 4.0 macros, indicated by the 'OOXML_XLM_MACROSHEET' heuristic. The VBA code appears to be obfuscated but likely attempts to download and execute a secondary payload. The presence of hidden sheets further suggests an attempt to conceal malicious activity.

Heuristics 4

  • 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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — 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
10f9340257f4c267d4a69e6c8fc82e9eb0317eb8a3d64a46dce6c041057f9290		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2406 bytes
vbaProject_00.bin
44c0de2e36f6e4280b1deaef9bf220b7cbbd2c9e4f026d1e70392bebdee1b9cf		 vba-project OOXML VBA project: xl/vbaProject.bin 25600 bytes
xlm_sheet_00.xml
c16e4cde2e69a3814f7e22498b8268ba35cc6459c7512f025029178c7ba2c2ba		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 763 bytes

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