Office (OOXML) / .XLSM malware analysis — malicious · 04e76637fcc5bcf8

MALICIOUS

Office (OOXML) / .XLSM

37.6 KB Created: 2021-04-07 07:02:41 UTC Authoring application: 16.0300

MD5: 5a88cb2b99d5a63d419278a412e91849 SHA-1: eb58c2d80d0e6e5d030c5b069dd28b6c658c24f8 SHA-256: 04e76637fcc5bcf8a11001b04d8f3db1ed6816352452dd75962199291859af38

90 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1566.001 Spearphishing Attachment

This Office macro-enabled XLSM file contains both VBA macros and Excel 4.0 macros, indicating a multi-stage approach to execution. The presence of these macro types strongly suggests an attempt to download and execute a secondary payload, likely leveraging PowerShell for further execution. The document body was heavily obfuscated and truncated, preventing a clear understanding of its lure, but the presence of macros and the critical heuristic firing for XLM macros point to malicious intent.

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 a VBA project — 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` `10f9340257f4c267d4a69e6c8fc82e9eb0317eb8a3d64a46dce6c041057f9290`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	2406 bytes
`vbaProject_00.bin` `44c0de2e36f6e4280b1deaef9bf220b7cbbd2c9e4f026d1e70392bebdee1b9cf`	vba-project	OOXML VBA project: xl/vbaProject.bin	25600 bytes
`xlm_sheet_00.xml` `c16e4cde2e69a3814f7e22498b8268ba35cc6459c7512f025029178c7ba2c2ba`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	763 bytes

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