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

Static analysis result for SHA-256 839311b6dd1f6581…

MALICIOUS

Office (OLE) / .XLS

332.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 6512a1d17c3326da2706c363d8775bba SHA-1: 5ffe12b2fc324cac1c7dd886e2bfbedfcdb33e5a SHA-256: 839311b6dd1f6581337352e9b3dbc2ee9ec111a1456df46c295cbd4b2e15fc5f
160 Risk Score

Malware Insights

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

The presence of Excel 4.0 macros, specifically an Auto_Open function utilizing dangerous APIs like RUN, strongly indicates a downloader. The heuristic firing for ShellExecute further supports the execution of external code. The embedded URL likely serves as the source for the second-stage payload, which is a common technique for malware delivery.

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://birdexim.com/ds/231120.gif

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
33b6a73d5f0d6eaa82513d86953f6aef905a69517ef33e4eba1db75f4a178a6f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6298 bytes

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