Qbot — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 ffd25a3236c74935…

MALICIOUS

Office (OLE) / .XLS

109.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 35cb8c4d555df799a5d108338165abc5 SHA-1: 1bed0416d0e67150e7b0f59fd4614a9f73d76f3d SHA-256: ffd25a3236c74935c76f513594b6fc2cd03b778d65d2b1b5735d99f97fb38567
262 Risk Score

Malware Insights

Qbot · confidence 95%

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

The file is an Excel 4.0 macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open macro that uses dangerous functions, specifically the RUN function, to execute code. The macro reconstructs and attempts to download payloads from three distinct URLs. ClamAV detection further confirms this as a Qbot 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 (3 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.Qbot11202120-9906200-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Qbot11202120-9906200-0
  • 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 https://decinformatica.com/AsqpQT6a2fl/t.html
    • https://novamiron.com.ar/SpV029NncEoH/t.html
    • https://mooca.imprimeja.com.br/uqJeyCxO9/t.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
230bdabe975ee04968fa009647a2319aa74c7d8f3acbeb25b6d04959c2937676		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 11292 bytes

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