Office (OOXML) / .XLSM malware analysis — malicious · 5c67f1248c0789b6

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 2c377ba5ffcdbdba76d3176a8808aa5a SHA-1: 3bf0112749c9e68471818f9149428198d2b376dc SHA-256: 5c67f1248c0789b69c6b34291bf62802d68e515a4f41d78262ab180a6f820ea7

310 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

This Excel macro-enabled document (XLSM) utilizes Excel 4.0 macros, which are known to be used for malicious purposes. The macros contain strings and formulas that call Win32 APIs like URLDownloadToFileA to download a payload from the specified URL. The use of dangerous XLM formula APIs such as REGISTER and EXEC indicates an intent to execute arbitrary code. The ClamAV detection further confirms its malicious nature.

Heuristics 7

Excel 4.0 macro sheet (10 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, GOTO, REGISTER, HALT 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.
Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS

Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
ClamAV: Xls.Downloader.GreenEnable06210-9869360-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.GreenEnable06210-9869360-0
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 10 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 10

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `8efd8094f7abd413303db6cd3bd761c2c5950f28478c2dbf981b14155d7123ac`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3220 bytes
`xlm_sheet_01.xml` `115d37a2938cb1eb4be3e1f7e040d86a710d0daac1aec0070cce28dd691c49a9`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	1785 bytes
`xlm_sheet_02.xml` `80e7e10992a865accecd248154f8993955ab288b63e292c3a068867b798fbb33`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	2651 bytes
`xlm_sheet_03.xml` `f788ff07287f4345ebde979af2962d950f9ee51261be208600834f863e989264`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	1730 bytes
`xlm_sheet_04.xml` `68030b89e6b4fa9175100e8b7d910608eca541d5ed4e2c0d66aeda37c494a807`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	1551 bytes
`xlm_sheet_05.xml` `4ebc5cb27ec4f2b547e1bd53bb611ec7d1683658b8c563ab084965c604bd18ef`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1550 bytes
`xlm_sheet_06.xml` `02c5359e6c25391c9e987c378ea1fa498b510bbd77700855700c1f66d26cff91`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.xml	1551 bytes
`xlm_sheet_07.xml` `0a36b8963427a06b07b518fde39e338399acae8b0375228e5cec6bdc4a42f657`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1553 bytes
`xlm_sheet_08.xml` `98386f020be407140630c7a14a4e79f58808acc942ac53553e969d84e0686ded`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1551 bytes
`xlm_sheet_09.xml` `e01811d7a24b25854e73f639fca1d02c34e5e3943023cd0c3b52664322cf12e5`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1703 bytes

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