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

Static analysis result for SHA-256 675916055b87abbf…

MALICIOUS

Office (OLE) / .XLS

392.7 KB Created: 2020-02-09 19:04:57 Authoring application: Microsoft Excel
MD5: b560e1fd0ab19e665aff2c3176999051 SHA-1: 5f4423e64b617163178b57e1355b389d62f2b2f6 SHA-256: 675916055b87abbf1879d269d03f079811c601f0e2002cf0bc8d326258867aab
262 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros that are configured to automatically execute upon opening. These macros utilize the RUN function, which is known to be used for executing arbitrary commands or downloading payloads. The presence of the URLDownloadToFile API call and the embedded URL 'http://synergyctsfl.com/falcon.exe' strongly indicate that the macro's purpose is to download and execute a second-stage executable.

Heuristics 6

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • 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
  • 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 http://synergyctsfl.com/falcon.exe
    • http://the.earth.li/~sgtatham�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
ffd547baec70f839032a21de09aae6c553377c7f547ef50340c9ed91073f1ad2		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 54845 bytes

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