Office (OOXML) / .XLSM malware analysis — malicious · baab3b0780e45d80

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 2df91ffcda07c9dc029555acba10e93f SHA-1: 66b5cb294da1d3f5a863a97fd3bd9dab73a75f6e SHA-256: baab3b0780e45d8065f01299472a252ba5a1657ee410530d892ccbb1afb29666

200 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1204.002 Malicious File

The file is an XLSM document containing Excel 4.0 macros. Heuristics indicate the use of dangerous XLM functions like CALL and EXEC, which are commonly used to download and execute payloads. The embedded URLs are highly suspicious and likely serve as the source for the second-stage payload. The macros likely establish persistence or download further malicious content.

Heuristics 5

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: CALL, EXEC, 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.
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.
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

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `5af50acff6cbbdc799bc87fa0ef670d47373a138e0b419c54b90db2d2951918f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	5611 bytes
`xlm_sheet_01.xml` `c3380cb57075605d0bde4a34749fe0ddd0456ab5ab63837fc53c08df29fa4a89`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	208663 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 shell/COM execution token(s).

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