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

Static analysis result for SHA-256 0a05732a462850c2…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 588b4b92ca04de3251a3cf360c8db237 SHA-1: 81a8f6d9b4d3bda826666edde7d25dcc6a9409bd SHA-256: 0a05732a462850c24727b3e3cd8cebf4e9b7d34e02d8da65c0ca097bd2e8e77e
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros with an Auto_Open entry, which is a critical finding. The macros utilize dangerous functions like RUN and CALL, specifically invoking a CALL to "Ke32" and "CryA" with concatenated strings derived from the document and a remote URL. This indicates the macro is designed to download and execute a second-stage payload from the URL https://fu5on.com/ds/231120.gif.

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://fu5on.com/ds/231120.gif
    • https://fu5on.com/ds/231120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
fc23abdcb2657b335d0fb386451be5be98110592c06d0600d83d33c16e5bacb2		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6295 bytes

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