Office (OOXML) / .XLSM malware analysis — malicious · d36bbd02b90a87cf

MALICIOUS

Office (OOXML) / .XLSM

153.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300

MD5: 570d5387a56bce79c6e54179bb87f6b4 SHA-1: 6632b7dbd4103fa2d976b9e2a57d21bbaba63cd6 SHA-256: d36bbd02b90a87cfa9c028cf43690395e2c2a554941309af7f2d0cfc59d18d67

250 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The file is an XLSM document containing Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous formula APIs like FORMULA.FILL and FORMULA to download a DLL from the reconstructed URL "http://cari.bbeanluxuryresort.com/wp-admin/3.dll" and save it as "C:\Datop\vima.ocx". This indicates a downloader functionality, aiming to fetch and execute a second-stage payload.

Heuristics 6

Excel 4.0 macro sheet (9 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: FORMULA.FILL, 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.
ClamAV: Xls.Downloader.GreenOffice02221-9938904-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.GreenOffice02221-9938904-0
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 12 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
- 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 9

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `dd67eb538715a00b2e93065c4d323605ad930e472c8b91844a402c4e23b60409`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	1346 bytes
`xlm_sheet_01.xml` `03bc2343445c3ac140f080a44f910ef8c73e2e4e15dd2c0b03ff30df719bba6a`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	2900 bytes
`xlm_sheet_02.xml` `e7b23dbb2e7b6aba3eca21d94728a4fc02006b4256eba3d080d4aebd86292246`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1417 bytes
`xlm_sheet_03.xml` `d36c7427a82a1110bc89c52917b3f4ca773def2f7bc8cd798a60772b126db324`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1415 bytes
`xlm_sheet_04.xml` `dc7796abe0fe08c483ab5c72669d344c10ac31ef7bbd05196f65708365adb679`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet3.xml	1417 bytes
`xlm_sheet_05.xml` `fcc4c31fbdc71bbc2ee85023800d751d96d3911d5b3d97f49cb82b70effc8db8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet4.xml	1414 bytes
`xlm_sheet_06.xml` `91f457d28b6be863946aaa078d23a2e0bb458c16f7d026c93da8be6dd58402ba`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet5.xml	1413 bytes
`xlm_sheet_07.xml` `c90506c3d91043abb68d7501520ab9a4381ca45a06c936ff289efcec3c9c337b`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet6.xml	1324 bytes
`xlm_sheet_08.xml` `37a5582b78c6265eecec3978b2636c25f78bb973fdd3e3e161f6da96bc97b692`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet7.xml	1249 bytes

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