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

Static analysis result for SHA-256 096d78cc7092bb4d…

MALICIOUS

Office (OOXML) / .XLSM

114.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 75f1565039392ebedcfd1157efc002d2 SHA-1: 3b39fba555327d6dfc7577a601a03933fe6ee7f4 SHA-256: 096d78cc7092bb4db5189c9b56245b1cdea76c88e84f01ab3bae1d41056ca693
190 Risk Score

Malware Insights

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

The file is an XLSM document containing both VBA macros and Excel 4.0 macros. The critical heuristics indicate the use of dangerous XLM functions like REGISTER and EXEC, which are commonly used to download and execute payloads. The Auto_Open macro in the VBA project likely triggers the execution of the XLM macros. The embedded URLs are highly suspicious and likely serve as the source for the second-stage payload.

Heuristics 6

  • Excel 4.0 macro sheet (2 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: HALT, REGISTER, GOTO, 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 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://45.138.157.63/
    • http://185.14.31.59/44313,6048108796.dat
    • http://45.138.157.63/44313,6048108796.dat
    • http://167.114.48.59/44313,6048108796.dat
    • http://185.14.31.59/
    • http://167.114.48.59/
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
93c5b5069f910db13d08004fd9c90d4a1d5d55d767ea4a26da2a888ea23d58c3		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 16398 bytes
vbaProject_00.bin
8cb40a0b5e5940f328e54000440cd3d6d132d980e84d59e085c3b458e3acf2f6		 vba-project OOXML VBA project: xl/vbaProject.bin 28160 bytes
xlm_sheet_00.xml
e8c6d8792e3e310b1df23866dbd173d4bec5628a83ded013e399050fdb4a128e		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 4502 bytes
xlm_sheet_01.xml
efa863078546591f10559e7ec4775260a2b46f2ed03bb71ea70b51048ee05558		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2004 bytes

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