Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 2586e3b1b27e0d6c…

MALICIOUS

Office (OOXML) / .XLSM

248.7 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: f6241843013cf4d4ff9a6e110bcb64f6 SHA-1: ac6233b7e548211f4932f92271c4352e2ba20180 SHA-256: 2586e3b1b27e0d6c485b4a7ac404c2d4c281c868bfb9ea4d31416553588300b8
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell

The sample is an XLSM file containing Excel 4.0 macros. The macros utilize dangerous functions like EXEC and FOPEN to write and execute a script file. Specifically, the macro reconstructs the path 'C:\ProgramData\gGTaFHkkJQrLOm.sct' and appears to be designed to download and execute this script, likely as a second-stage payload. The use of these low-level functions and the obfuscated script path indicates a malicious intent to bypass standard security controls.

Heuristics 5

  • 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.
  • 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: FOPEN, FWRITE, FCLOSE, EXEC, HALT 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.

FilenameKindSourceSize
xlm_sheet_00.xml
79601546c8719ce4a848c74ded9c12bbbbf8003275c2ec43cd94ff0f5a844a46		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 706455 bytes

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