Office (OOXML) / .XLSM malware analysis — malicious · bc6256f31ef12f54

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 121c7ef74deb0b2aca442d971035360d SHA-1: 428defea926e454a3ed23ab760c1fe52104b918e SHA-256: bc6256f31ef12f5400d0ffce9f9eab4b24c515b2e70cefe9a0b6ce0c78a95524

208 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1204.002 Malicious Link: Malicious File

This XLSM file contains Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous functions like CALL and EXEC to download and execute payloads from external URLs. The document body explicitly lists two URLs that are likely used to host the malicious payload, suggesting a downloader attack pattern. The presence of hidden sheets further supports the concealment of malicious activity.

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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