Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 6af31d2a6892ad0b…

MALICIOUS

Office (OOXML)

38.0 KB Created: 2020-09-20 21:17:44 UTC Authoring application: Microsoft Excel 16.0300
MD5: 5373e77e0f5083dd701ca4497fd64c82 SHA-1: 07f11e1b4792ef663ab1e5df35fe32a4af19fb3c SHA-256: 6af31d2a6892ad0be9637aabdac93275d0f2390366f813c65b6a8f817623f6da
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

This Excel file contains Excel 4.0 macros, which are known to be used for malicious purposes. The macros contain EXEC functions that download a payload from 'http://iurl.vip/fqarx' to the temporary directory as 'FoGzR.exe' and then execute it using PowerShell. The use of EXEC and direct Win32 API calls indicates a high likelihood of malicious intent.

Heuristics 6

  • 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: EXEC 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.
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Hidden worksheet (veryHidden) 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://iurl.vip/fqarx
    • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
6411d14379b9cd0254a26791664459a6c16757e868c87021cc6478fd1674b806		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1637 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).

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