Office (OOXML) / .XLSM malware analysis — malicious · ecbba9047f7834d0

MALICIOUS

Office (OOXML) / .XLSM

37.4 KB Created: 2021-04-20 07:52:58 UTC Authoring application: Microsoft Excel 16.0300

MD5: 8de38314e26c490b25af8660dccfb1dd SHA-1: f82e1ac72e0d161e591ca81a973085d4c11105cc SHA-256: ecbba9047f7834d0ab6d3f9b0e6a5b9dd3d338040045ad3c2d8e0a0efcd9402b

88 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1059.001 PowerShell T1204.002 Malicious File

The file is an XLSM document containing Excel 4.0 macros, a known technique for executing malicious code. The presence of VBA macros and a hidden sheet further indicates malicious intent. The macros likely download and execute a second-stage payload, though the specific URLs are benign schema references. The document body is heavily obfuscated and does not provide direct clues to the user-facing lure.

Heuristics 4

Excel 4.0 macro sheet (1 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.
VBA project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 2 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

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `5f96018d58fcdb55a386b481fb7b908424c9f7468e2a53bd909a71a6eaefc842`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	2507 bytes
`vbaProject_00.bin` `6f4d88a868c1afb2d0f503c937aa3269e8ffdf15853b084c7a2f95ccf8793fee`	vba-project	OOXML VBA project: xl/vbaProject.bin	22016 bytes
`xlm_sheet_00.xml` `c16e4cde2e69a3814f7e22498b8268ba35cc6459c7512f025029178c7ba2c2ba`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	763 bytes

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