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

Static analysis result for SHA-256 84558e229b112f64…

MALICIOUS

Office (OOXML) / .XLSM

92.6 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: bb89c6f12bb7e6615bab48b1af6fa0f0 SHA-1: 4aa28ceddfa9de92dfd72a351575fa46c6e1d942 SHA-256: 84558e229b112f64c102cb38404f83d6f865ef89df90ffd83d8bbb60e8427dde
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic for Applications T1204.002 Malicious Link: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell

The sample is an Excel 4.0 macro sheet that uses dangerous functions like CALL and EXEC. The document body contains a list of URLs that are likely used to download and execute a second-stage payload. The presence of these functions and the embedded URLs strongly suggest a malicious intent to deliver malware.

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.
  • 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: EXEC, HALT, CALL, FORMULA.FILL 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.
  • 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
b2aa95d3b3a02526f200b3d969c9988b4d5832e6c13ac8dcb3a1d9eb395b3574		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 213450 bytes

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