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

Static analysis result for SHA-256 79ef5871ecacd598…

MALICIOUS

Office (OOXML) / .XLSX

24.5 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 35723b78b4b075f1c8cd59648d2f24be SHA-1: c71f60127835362f0ffbf619475fcdd9a70f137f SHA-256: 79ef5871ecacd598029e1abb247f74d40f85a987d6d4100f6bfe6fb293bcf478
124 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 macros, which is a critical finding. These macros contain strings indicating WinAPI calls for downloading files and executing them, such as URLDownloadToFileA and ShellExecuteA. The embedded URL https://craftsmadebyfaith.com/ds/29.gif is likely used to fetch a second-stage payload. The macro's intent is to download and execute a file from the internet.

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. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
  • Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS
    Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
  • XLM payload URL string (1 URL) info OOXML_XLM_PAYLOAD_URL
    An Excel 4.0 (XLM) macro-sheet workbook with download/execute evidence carries a literal http(s) URL stored as a (often UTF-16) string in the shared-string table or a cell. This is the next-stage payload host referenced by the macro download chain (URLDownloadToFile/ShellExecute); surfaced as an IOC.
  • 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 https://craftsmadebyfaith.com/ds/29.gif

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
99a6a52acb8f5c734f6d86faf89e0637a94ac99f953aa583d2658b47d2e1f9b9		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 194023 bytes

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