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

Static analysis result for SHA-256 04c5391360569990…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 41c0345cd47aed7039444b6542e3a2b0 SHA-1: d7ae75eb167044126ec23a049e07598523025401 SHA-256: 04c539136056999029d62f85301594dffbbdaab8ccb00f30e063f23e7fddf5b5
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, indicating automatic execution upon opening. The macros utilize dangerous functions like RUN and CALL, and attempt to construct strings that likely form executable commands or URLs. Specifically, the macro attempts to call functions that appear to download and execute a payload from the provided URL, 'https://oyefauji.com/ds/261120.gif'. This behavior is consistent with a macro-based downloader.

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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