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

Static analysis result for SHA-256 6cc9321adcdcab16…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 2ff9e4b2ee8ebf8d1e8117dfe79025c8 SHA-1: 1107ae160306437380803bb9f597089ab85ad8ee SHA-256: 6cc9321adcdcab1614ce53cbc696635e42fac0cc8f2b4336357f191da7cc1ef3
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, which is a critical finding. These macros utilize dangerous functions like RUN and CALL to execute code, specifically referencing functions that appear to construct strings for execution, such as 'Ke' + 'l32' and 'Cr' + 'yA'. The presence of ShellExecute API references further indicates malicious intent. The macro attempts to download a file from the provided URL, likely to execute a second-stage payload.

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://ump.edu.pe/ds/261120.gif
    • https://ump.edu.pe/ds/261120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
56d07016068e454a1af96b6cee33e5364bc7ae97582ff73833a2c41ba0035917		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6675 bytes

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