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

Static analysis result for SHA-256 86520669d37c2088…

MALICIOUS

Office (OOXML) / .XLSM

112.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: b239b80089b56a54d6b47039e91011dd SHA-1: c7635264eb179b2cf7daae29e34e9cc38c10bf3f SHA-256: 86520669d37c2088b16cc5c4822c8838ce5948f0de119cd61b923fdb00fb4db1
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The sample is an XLSM file containing Excel 4.0 macros and a VBA Auto_Open macro. The XLM macros utilize dangerous functions like FORMULA, REGISTER, and EXEC to download a payload from one of the provided URLs. The VBA script calls into the XLM macros, indicating a layered execution approach. The presence of these elements strongly suggests a downloader or initial access mechanism.

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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