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

Static analysis result for SHA-256 634e902423a9d6d5…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: aa34d47e77ec03fe8df03f517c54813d SHA-1: 687cd35abb5609d5507f4bcc04d0040a8fa7efa9 SHA-256: 634e902423a9d6d5a1c042ff344e86c5688977ee1084d15d45075f32e2b6d032
242 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros that are triggered by the Auto_Open function. These macros utilize dangerous formula APIs, including RUN and CALL, to execute code. The script attempts to construct strings like 'Ke' + DocuSig!BY80 + 'l32' and 'Cr' + DocuSig!BY92 + 'yA', which likely form part of a command to download and execute a second-stage payload from the embedded URLs.

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://tured.net/ds/261120.gif
    • https://tured.net/ds/261120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
4805caad40efa88359221773489543a181039fb59e7111454d99230bce3bd306		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6674 bytes

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