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

Static analysis result for SHA-256 a412aef4e6aa082a…

MALICIOUS

Office (OLE) / .XLSX

105.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 794e77c7a4220025443fe344f14c3b48 SHA-1: 01d50f11933be842dfe6bd891487d9d1e19577fa SHA-256: a412aef4e6aa082a01526af7afca8124caab690ca95735e9333bf0630c834962
262 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution

This malicious XLSX document contains an Auto_Open macro that utilizes dangerous formula APIs and reconstructs URLs from cell arrays. The script concatenates strings to form the following URLs: 'https://dongarza.com/gJW5ma382Z/x.html', 'https://headlinepost.net/3AkrPbRj/x.html', and 'https://produtoratime.deelenco.com.br/9E6Y322u/x.html'. These URLs are likely used for downloading additional payloads or executing further stages of the attack, consistent with user execution techniques (MITRE T1204) and scripting file impersonation (MITRE T1076). ClamAV detection supports this assessment.

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://dongarza.com/gJW5ma382Z/x.html
    • https://headlinepost.net/3AkrPbRj/x.html
    • https://produtoratimedeelenco.com.br/9E6Y322u/x.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
2d69a468deda6ef532bccca4917aca41c7abe1a521540a9fe9f977b5d05e05bf		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 11378 bytes

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