Office (OOXML) / .XLSM malware analysis — malicious · 6aee0b23934b7a69

MALICIOUS

Office (OOXML) / .XLSM

109.5 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300

MD5: 73b1310df9c7e43e8b18510957003c09 SHA-1: 10ab469c82e84a07dabd7295c382925b4be00f8c SHA-256: 6aee0b23934b7a698172defb41299c5b58dc8f079de59822e25b1b37e2479c0a

210 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File

The sample is an XLSM file containing Excel 4.0 macros, indicated by multiple critical heuristic firings including the use of dangerous functions like EXEC and CALL. The macros are designed to execute code, likely downloading a second-stage payload from the URLs found in the document body and embedded scripts. The presence of the EXEC function with arguments pointing to potential payload filenames like '..\duron.bnm1' and '..\duron.bnm2' strongly suggests a downloader or dropper functionality.

Heuristics 6

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: EXEC, HALT, FORMULA, WORKBOOK.HIDE, CALL 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.
Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 1 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 https://immobiliareneri.casa/drms/ind.html
- https://gidbasket.com/drms/ind.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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `7d118572f5fe7d6ff43ed02ebd45ba65e8abef406e7a780baf6c364273fc6add`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	3454 bytes
`xlm_sheet_01.xml` `fbe5e7dbb69c9673a292262e360301ab1ec7a303eb74e3af592196e67c71385f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	205673 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 shell/COM execution token(s).

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