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

Static analysis result for SHA-256 5a9f39634b38c74c…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 75ef6b8aa4654bef37f13102854a12fb SHA-1: 3bdcdf9a17be2d6918632d36e8c480c745065488 SHA-256: 5a9f39634b38c74cb35cd6119b1fa2e6771c539d7a7ec007e6251160d532d5b2
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, which is a critical finding. The macros utilize dangerous functions like RUN and CALL, and specifically construct a call to 'kernel32.dll' with arguments derived from other cells. The macro also contains a URL, 'https://chica.media/ds/231120.gif', which is likely used to download and execute a second-stage payload. This indicates a downloader or dropper functionality.

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://chica.media/ds/231120.gif
    • https://chica.media/ds/231120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
f47affe8c13bcf147c60cdfcb7548aa5c789e981f4872a53ebdda3b841e12f12		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6059 bytes

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