Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 ec1a0bed50ba50e2…

MALICIOUS

Office (OOXML)

83.4 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: a30bab2cf4c33100e8ac7a1a8c1cece4 SHA-1: 52c1bda203303ec37f88582dd2a58c80c2706b43 SHA-256: ec1a0bed50ba50e29b43e680dc66c3f725ec288023a77a21522cdd877ed1af9f
190 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, indicated by the 'OOXML_XLM_MACROSHEET' and 'OOXML_XLM_AUTOOPEN_DEFINEDNAME' heuristics. These macros utilize dangerous functions like 'CALL' and 'EXEC' to download a DLL from 'http://162.248.225.97/1.php' and save it as '..\fhgajkla.dll'. The script then attempts to execute this DLL using 'regsvr32 -silent ..\fhgajkla.dll', suggesting a downloader or dropper functionality.

Heuristics 5

  • Excel 4.0 macro sheet (4 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.
  • 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: HALT, FORMULA 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 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 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

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
d505811de5a883bedf8e0c2084c2b3d64cec37da9aca77dc270e4e2ea6d7486d		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1456 bytes
xlm_sheet_01.xml
a8b153a062d4aa47a7768cbe416affb98aae83e032b07f2f3a7351700d9ff620		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 1494 bytes
xlm_sheet_02.xml
cdf41698cded2e38132966777a3663575d2cfd1ea535f5505f7b546338e5a1c1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1386 bytes
xlm_sheet_03.xml
5e66e28f48eff5fa338d6f58cf0e9b1464f6c796c9bdf00ca35e20bac7f14dbc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 1510 bytes

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