Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 0cbeea56b002bef1…

MALICIOUS

Office (OOXML) / .XLSX

112.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 1f3ef398feb8d6ae745df227c0b4da43 SHA-1: 9ad40b86030d0368b08d729195b7ee39c5b75953 SHA-256: 0cbeea56b002bef19d886c34d77abc7727a2fbec3c616d6e3f5ca8cfdacc8902
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains critical Excel 4.0 macros that utilize dangerous functions like FORMULA, HALT, GOTO, REGISTER, and EXEC. These functions are known to be used for downloading and executing payloads. The Auto_Open VBA macro further orchestrates the execution by calling functions from a hidden sheet, likely initiating the download from one of the provided URLs. The presence of these functions and the Auto_Open macro strongly suggests an intent to download and execute a second-stage payload.

Heuristics 6

  • Excel 4.0 macro sheet (3 sheet(s)) critical 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.
  • Dangerous XLM formula APIs: FORMULA, HALT, GOTO, REGISTER, 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.
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 3 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://45.84.1.195/
    • http://185.82.219.131/
    • http://185.82.219.131/44313,6048108796.dat
    • http://45.84.1.195/44313,6048108796.dat
    • http://185.238.0.40/44313,6048108796.dat
    • http://185.238.0.40/
    • http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
336c54ce55c4f97b2e578c36c24779a5cbf4053bf1babc3f97ec244f65df85ae		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1451 bytes
vbaProject_00.bin
82f147ef4622124b990fa97fb82d52ce21a1a719f45158e458ccdd0608e1339c		 vba-project OOXML VBA project: xl/vbaProject.bin 16384 bytes
xlm_sheet_00.xml
7bda064f9dd7461df3562edd896d831d9cbcce6b3896f4ceedf5c0e558bfe6d1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 3807 bytes
xlm_sheet_01.xml
195a22194deb18d457e7a276044a8954c5a468f56b51b6a1ff34e52b2b6585ae		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2129 bytes
xlm_sheet_02.xml
790f162dfe4d36146f6098416bb54d0d0a33d67d88c8fea35d57cce261bdd8f0		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1943 bytes

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