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

Static analysis result for SHA-256 6912e628cbc4e57b…

MALICIOUS

Office (OLE) / .XLSX

145.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 105ca3ea41e6ddde7f18057de7f2f1ee SHA-1: 09a74075e91dc9524f1b771bb2774976810c345b SHA-256: 6912e628cbc4e57bf69375b65cef6a7fd5f71c08d61702305c073839438d8b32
262 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, including an Auto_Open function that utilizes dangerous formula APIs. These macros are designed to reconstruct and download payloads from multiple URLs, as indicated by the embedded URL heuristics and the reconstructed URL strings in the document body. ClamAV detection further confirms its malicious nature as a downloader.

Heuristics 6

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • URL reconstructed from XLM cell array (5 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • ClamAV: Doc.Downloader.EmotetRed02222-9938635-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02222-9938635-0
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • 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://www.numberscare.com/apocholic/0zs1GFW8z/
    • https://kratomcoupons.com/wp-snapshots/rRAWKjQIH4Jlc/
    • http://www.campingforacuresl.com/newdir/yKGYdIxMOqdNzaxeA7G/
    • https://coffee.devtechnosys.info/app/8UP4CHdtji/
    • https://dautuchungkhoanquocte.com/wp-admin/X0vaYKzvcqLdmO/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
71a011c6654bf0f86fe42dabbb7815a8e04c6ae15b5b70864945acbb6f82ced0		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6768 bytes

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