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

Static analysis result for SHA-256 9fb990038235c52c…

MALICIOUS

Office (OLE) / .XLSX

332.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 65e8fa4e21b5370861cc9517d89fec48 SHA-1: 64dd0d9dfbd4b7332229994de80f8710fda5a9d1 SHA-256: 9fb990038235c52cd2e220cc5434ca5cbb579cd644a3583c833e4fa45f0d2c9d
160 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The SC_STR_SHELLEXEC heuristic and the presence of 'ShellExec' in the document body suggest that the macro attempts to execute an external command. This is further supported by the embedded URL, which is likely used to download a secondary payload. The ClamAV detection confirms the malicious nature of the file.

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 https://19racks.com.br/ds/151120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
4d5531650e0faf8764ddd7b14e6947143c32308cbf699d36f8845764b3b4560a		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 5603 bytes

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