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

Static analysis result for SHA-256 5b9bcb00ded66bc8…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 03b7ddc0464257c33a7e3d64251e9d3d SHA-1: 7e335b7c449ff6def20f24aeb56f19bbb9531961 SHA-256: 5b9bcb00ded66bc832bb620824528e6d19d004803a2d6513b41099ef1613dabf
242 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros with an Auto_Open entry, indicating it's designed to execute automatically upon opening. The macros utilize dangerous functions like RUN and CALL, and attempt to construct strings that likely form API calls or URLs for downloading and executing a secondary payload. The embedded URL https://bgms.co.in/ds/261120.gif is a strong indicator of a downloader. The use of ShellExecute API further supports the execution of external code.

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://bgms.co.in/ds/261120.gif
    • https://bgms.co.in/ds/261120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
e213645668ce9f5d68f4226afb5b9b5e6c2ad49807658d9b833212b471c7c00d
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6675 bytes