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

Static analysis result for SHA-256 e835f8543e5b974d…

MALICIOUS

Office (OOXML) / .XLSM

30.0 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 16.0300
MD5: e20862ac9ce3747bd715f0f94e28ef09 SHA-1: 506032a54f13133c43a60b840f16909b92fc24f7 SHA-256: e835f8543e5b974d652220b0489f0de4f7eebfb63c489d58b44eeee047becabc
108 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious Link: Malicious File

This XLSM file contains Excel 4.0 macros, which are known to be used for malicious purposes. The heuristics indicate the use of dangerous XLM functions like REGISTER and FORMULA.FILL, suggesting the macro is designed to download and execute a second-stage payload. The presence of a suspicious URL, 'http://schemas.micr', further supports this assessment.

Heuristics 4

  • Dangerous XLM formula APIs: REGISTER, HALT, FORMULA.FILL 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.
  • Excel 4.0 macro sheet (1 sheet(s)) high 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.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 5 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.micr
    • http://schemas.openxmlformats.org/spreadsheetml/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
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
b7d0c28a7a68b5ffe892933497a79b65a06888c887401dd098cd6913fe79d89b		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 40181 bytes

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