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

Static analysis result for SHA-256 9749d12356b7e36a…

MALICIOUS

Office (OLE) / .XLSX

329.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 027e15ab7ef85e9220a45225e0f381d4 SHA-1: faeb6fe076f2236a2ec912b2296875d9da553c73 SHA-256: 9749d12356b7e36a4c2493e6914e19d7289981e5cfa058c799597760260a5f36
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell T1204.002 Malicious File

The file contains Excel 4.0 macros, specifically an Auto_Open macro that utilizes dangerous functions like RUN and ShellExecute. This indicates the macro is designed to execute arbitrary commands or download additional payloads. The embedded URL likely serves as the source for this secondary payload. The ClamAV detection name 'Doc.Downloader' further supports the 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 https://btchs.com.br/ds/161120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
c7e4e7ed3c1ce4a0357cad7ea2d4765567912ff9637c55ef23ac64833b3a62a6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6274 bytes