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

Static analysis result for SHA-256 73da9a594861668d…

MALICIOUS

Office (OLE) / .XLSX

329.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: f32dd90fcd10f0c5b446b55281418436 SHA-1: 080f57dfe54147ddf5a0a59de53e889408c01c74 SHA-256: 73da9a594861668d242dbf6b759798c179e85333b145be80ca1f8421f3aa7821
242 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros with an Auto_Open entry, indicating it will execute automatically upon opening. The macros utilize dangerous functions like RUN and CONCATENATE, and reference an embedded URL, suggesting it is designed to download and execute a second-stage payload. The ClamAV detection 'Doc.Downloader.Docusign0521-9864805-0' further supports its role 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.
  • ClamAV: Doc.Downloader.Docusign0521-9864805-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Docusign0521-9864805-0
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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://btchs.com.br/ds/161120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
c7e4e7ed3c1ce4a0357cad7ea2d4765567912ff9637c55ef23ac64833b3a62a6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6274 bytes

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