Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 ad0ee613b5a98b20…

MALICIOUS

Office (OOXML)

660.7 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 93caac0fc3189ad42b746622715559e4 SHA-1: a92ac451778c3d2d45c50bcfbc96d163d40f60d2 SHA-256: ad0ee613b5a98b20f98c933c6e692d343496b17bf55facc05918976bae0d2370
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros that utilize dangerous functions like REGISTER and EXEC. These macros are designed to download a file named 'Kro.fis' from the IP address 104.168.166.222 and execute it. The presence of these functions and the download/execute pattern strongly suggest a malicious downloader.

Heuristics 5

  • Excel 4.0 macro sheet (2 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: REGISTER, RUN, 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 4 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://104.168.166.222/images/darkmoonlite.png
    • http://104.168.166.222/images/shortearthget.png
    • http://104.168.166.222/images/lovemetertok.png
    • http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/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
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
40ddb28feb0f81c4ec854fd8ba2b194a30a086ab4790b6dad4d44c8b8ae4ad9f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 2083 bytes
xlm_sheet_01.xml
24a9abf86273767cb6dc3ef5123101e29e32d244c5f84ae5cf491b44ffd6397a		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1651 bytes

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