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

Static analysis result for SHA-256 72b9fdb8c11e4551…

MALICIOUS

Office (OOXML) / .XLSM

110.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 8da59aa27c406a936fbfbb812e6b3793 SHA-1: 1cdffa464ffd1756a5af38f9c74d65591f0a377d SHA-256: 72b9fdb8c11e45519c84f79f3de1cb6ebb04cd91ce43be8dcc754d9b487fcc24
190 Risk Score

Malware Insights

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

This Excel document contains critical Excel 4.0 macros that utilize dangerous functions such as CALL and EXEC. These functions are capable of directly invoking Win32 APIs, which are likely used to download and execute a second-stage payload from one of the embedded URLs. The Auto_Open VBA macro also appears to be present, further indicating malicious intent.

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: 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://91.211.91.83/44313,6048108796.dat
    • http://190.14.37.46/44313,6048108796.dat
    • http://185.244.149.204/44313,6048108796.dat
    • http://91.211.91.83/
    • http://190.14.37.46/
    • http://185.244.149.204/
    • 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
75218b3f0bb17eeec5572784caf45beb820d0c1786c79b4827590e90358f3168		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 796 bytes
vbaProject_00.bin
68abdc7272e01a8d5f23efd6d2f6ad7622be560008d64f00989b7abcdeaf1e49		 vba-project OOXML VBA project: xl/vbaProject.bin 13824 bytes
xlm_sheet_00.xml
7f5df2ff1665161288b5ce187d9f08cbead06b57e6e53e1569d3e38eefc6f10f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 4285 bytes
xlm_sheet_01.xml
a5fc80b1569128bd0323daacf4b0484b147d9d37755aacc26435ea011bd9f0cd		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2111 bytes
xlm_sheet_02.xml
a6c079d2a564b952bdc7f60d49402489a374e91f07f8b51ef328523d2a650900		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1944 bytes

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