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

Static analysis result for SHA-256 02761cd66c29a43d…

MALICIOUS

Office (OLE) / .XLSX

332.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: f88819aca9dac9a65d6b3e0bcb8cce8a SHA-1: c56dd86c07f64992f5d0218bb6343e8e649eed09 SHA-256: 02761cd66c29a43dbfc328f673ab9208aa471dcb03e93919f34e66d53bfb7a12
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, including an Auto_Open entry, which is a critical indicator of malicious intent. The macros are designed to execute a URL, specifically 'https://19racks.com.br/ds/151120.gif', likely to download and execute a secondary payload. The presence of ShellExecute API calls further supports the execution of external commands or files.

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://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