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

Static analysis result for SHA-256 a66312a1e8fdc5cc…

MALICIOUS

Office (OLE) / .XLSX

329.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: b1d9f11d0bf914621c40d0b4e6e2317f SHA-1: 0c07e8ee875947ceaeee9e2ef144c0ee45414ca0 SHA-256: a66312a1e8fdc5cc4d9d32442d2fc0b67b7986470062d5e37fdf89ea772303c8
160 Risk Score

Malware Insights

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

The presence of Excel 4.0 macros, specifically an Auto_Open macro utilizing dangerous functions like RUN, strongly suggests malicious intent. The heuristic firing for ShellExecute API further indicates that the macro is designed to execute external commands. The embedded URL is likely used to download a secondary payload. The ClamAV detection name 'Doc.Downloader.Docusign0521-9864805-0' also points to a downloader functionality.

Heuristics 5

  • 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
  • XLM Auto_Open with dangerous formula APIs high 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.
  • 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://ippp.co.zw/ds/161120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
de64c8aedb9841e9622ce89b4c2a59532a2613bac9a0b05117fd5443ba276b2f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7888 bytes

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