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

Static analysis result for SHA-256 970a783ce4bb121f…

MALICIOUS

Office (OOXML) / .XLSM

102.1 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: 8aec19109b57c74cb67d4b89f3b0803c SHA-1: 10341b41efd4e1f33da5064973521cc61c7ee3de SHA-256: 970a783ce4bb121f6691c684cc00b3c3ec159028d4b1fa39d1f9f13d31fac24f
130 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros that utilize dangerous functions like FOPEN, FWRITE, FCLOSE, and EXEC. These functions are used to construct a path and likely download and execute a second-stage payload. The reconstructed path is C:\ProgramData\tPrisecQvMt mOI.vbs, which is then likely executed as an .exe or .dll. The presence of hidden sheets and the use of these low-level functions indicate a malicious intent to download and run further malware.

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.

FilenameKindSourceSize
xlm_sheet_00.xml
c15807d17d07cd533ab63ed63d96f5836322eb53207101a41d44d88875f1c4c2		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 5191 bytes

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