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

Static analysis result for SHA-256 5a408f1993b79a6a…

MALICIOUS

Office (OLE) / .XLSX

332.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 6b65e1b311bd762234bf57b73534e080 SHA-1: 6a42ccf0e7e1756f2d53bca67b13741e4d41da16 SHA-256: 5a408f1993b79a6ae3b0d0a87737c18cec48a2b34f2095b9b8f1f8b5b7fbd6f0
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros with an Auto_Open defined name, which is a critical indicator of malicious intent. The macros utilize dangerous formula APIs, including RUN, to execute code and reference an embedded URL. This suggests the macro is designed to download and execute a second-stage payload from the URL http://cloud.c-tes.gr/ds/151120.gif.

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 http://cloud.c-tes.gr/ds/151120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
89aad7b8576d8f84c1934acd2fc0826a9bcea7c600ce1ac7e8579bafe1fef843		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 5602 bytes

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