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

Static analysis result for SHA-256 e60dd6a3b885f9ed…

MALICIOUS

Office (OOXML) / .XLSM

71.7 KB Created: 2020-12-01 10:39:37 UTC Authoring application: Microsoft Excel 16.0300
MD5: 66bcae29b9c1137ec79828c06051c0fc SHA-1: 1d81f960203b6d945067b8e768570cf7fd77f927 SHA-256: e60dd6a3b885f9ed3356cd62c4d53590f255509fc07c9e4aa31c0e1fb16673e5
150 Risk Score

Malware Insights

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

This XLSM file contains VBA macros that leverage Excel 4.0 macro sheet functionality. The VBA code decodes a string into 'revis' and then executes it using the Run function, indicating it's designed to download and execute a second-stage payload. The presence of a hidden sheet and the use of ActiveX event handlers further suggest an attempt to conceal malicious activity.

Heuristics 5

  • VBA ActiveX event runs worksheet-decoded XLM formulas critical OLE_VBA_ACTIVEX_XLM_CELL_STAGER
    VBA code attached to an ActiveX/UserForm event reconstructs formula text from worksheet constants using Split/Replace/Mid or character shifting, then executes it through ExecuteExcel4Macro or Run. This is a high-confidence malware stager that hides XLM formula execution in sheet cells; it is not a document-parser CVE.
  • 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 vbaProject.bin — VBA macros present
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
34d40ee284ed49750db61e64361eecbcb6adcf550ff1b64bcbbea7353c616d7e		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1525 bytes
vbaProject_00.bin
2403678c34164098d1ae9d881e7a599a700e8c26e91d3f20067a202ece628a81		 vba-project OOXML VBA project: xl/vbaProject.bin 16896 bytes
emf_00.emf
4609916d8bdbc79e29612828ccd046cae14d7ddc0bfea0db84520ad5f180a00d		 ooxml-emf OOXML EMF part: xl/media/image1.emf 1408 bytes
xlm_sheet_00.xml
c77998eae21f87e28e77a0b0752a67d2a6486bd14af15ddec5704a6fbd8a0b74		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 815 bytes

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