Office (OOXML) / .XLSM malware analysis — malicious · 012537189806608a

MALICIOUS

Office (OOXML) / .XLSM

113.8 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000

MD5: 310442f6536c1f5b5b29b8ea15481a72 SHA-1: 7ad167eaa7136f534201d86806bb3aa3b15dccee SHA-256: 012537189806608adcc4578c40a84129fec28f05ffb14ff7b6b0a8fe8b7c83ef

130 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1105 Ingress Tool Transfer

This Excel 4.0 macro-enabled document (XLSM) contains heuristics indicating the use of dangerous functions like FOPEN, FWRITE, and EXEC. The macro code attempts to construct a VBScript payload by concatenating strings and writes it to 'C:\ProgramData\wxMAAwSyOR.vbs'. This indicates a downloader or dropper functionality, aiming to execute a secondary stage.

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.
Dangerous XLM formula APIs: FOPEN, FWRITE, FCLOSE, EXEC, RETURN 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.
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 http://schemas.openxmlformats.org/spreadsheetml/2006/main
- http://schemas.microsoft.com/office/excel/2006/main
- http://schemas.openxmlformats.org/officeDocument/2006/relationships

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `cb5e08d830b7b91429db2b9fd57d4852c8167888144c6793d1eacd971c064aac`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	5354 bytes

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