Office (OOXML) / .XLSM malware analysis — malicious · c60b66589bdc1025

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: f0c0419067521dc33bda514a4c8252e7 SHA-1: 64728743138d7bab04b6d21766c4a1a5b27facb9 SHA-256: c60b66589bdc1025723f31d25a46f0f4e402ba7716420eca47e1d954f3b1d331

130 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous functions like FOPEN, FWRITE, FCLOSE, and EXEC to write a second-stage payload to disk and then execute it. Specifically, the macro attempts to write to 'C:\ProgramData\GopzYoQ1QO.vbs' and then execute it using the EXEC function. The presence of a hidden sheet further suggests an attempt to conceal malicious activity.

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` `60c99eee1f467a196ac11008b2d57727a87162a69239b25af637b137eed6a5cf`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	5411 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.