Office (OOXML) / .XLSM malware analysis — malicious · bc3b80cd01acfa43

MALICIOUS

Office (OOXML) / .XLSM

86.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 14.0300

MD5: 23f5dffc57f276dcc8665a92448479ce SHA-1: f7104e02fdc73c052da867d757617ab1a754bc73 SHA-256: bc3b80cd01acfa43dc43bb36681e6744576fc4b26959c3fc55904d3c562b9871

180 Risk Score

Malware Insights

MITRE ATT&CK

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

This XLSM file contains Excel 4.0 macros, specifically utilizing dangerous functions like CALL and EXEC. The document body and extracted URLs indicate the macro's intent is to download and execute a second-stage payload from the provided URLs. The use of these functions directly from XLM macros bypasses typical VBA security and is a common technique for initial payload delivery.

Heuristics 4

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.
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: WORKBOOK.HIDE, EXEC, CALL, 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.
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 https://thersnyc.com/fxcS6exSJr0/04.html
- https://justverify.online/ZKrubZZn5V/04.html
- 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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`emf_00.emf` `442eb38c1c88060cf62c1fd88f48f9b8961edd687fe9250cf42ff79baf20ccae`	ooxml-emf	OOXML EMF part: xl/media/image1.emf	296536 bytes
`xlm_sheet_00.xml` `e2d0c69c580969a640d565ee7f4c9f99c84cac5b5d64c997ece3e584778305c8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1638 bytes
`xlm_sheet_01.xml` `8877d538d505af08b0c326ee597bc05eb27a221881758da594814f19457722a4`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	3709 bytes

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