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

Static analysis result for SHA-256 b68f3d5500df3f8d…

MALICIOUS

Office (OOXML) / .XLSM

98.5 KB Created: 2020-04-23 12:26:24 UTC Authoring application: Microsoft Excel 16.0300
MD5: 08ce993617e54d478ba33852b1428443 SHA-1: 25ecb92df42aba746d914d3832148693228fa2f5 SHA-256: b68f3d5500df3f8de0527d08e4bcacedd23a6d6d8da246dec168696bd4caaa03
202 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The sample is an Excel macro-enabled spreadsheet (XLSM) that uses Excel 4.0 macros. It contains a lure to enable content, common in macro-based malware delivery. The XLM macros utilize dangerous functions like REGISTER, which can be used to download and execute payloads. The document body text explicitly instructs the user to 'Enable Editing' and 'Enable Content' to view the content, reinforcing the lure. No specific family could be identified, but the techniques suggest a downloader or initial access 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.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: REGISTER, HALT, RETURN critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
4eb623f0e3776705bd2fd58cbb38718dc8d11b950b827a09ed1b6646963190c0		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 491469 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.