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

Static analysis result for SHA-256 639dd2f662dbdfc9…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: f41433bcdf1b7bbd312864d1dbc926ab SHA-1: 6e36cb5681e7dba3717c942af50ba46f75f79cc5 SHA-256: 639dd2f662dbdfc96d6b12c4ec1356532ed0c4a9995328ed4dbbb277ec490ce2
242 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros with an Auto_Open entry, which is a critical finding. These macros utilize dangerous functions like RUN and CALL to execute code. Specifically, the CALL function attempts to execute 'Ke32' and 'CryA' using arguments constructed from concatenated strings and cell references, ultimately leading to the execution of a payload from the URL https://chica.media/ds/231120.gif. This indicates a downloader functionality.

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://chica.media/ds/231120.gif
    • https://chica.media/ds/231120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
f47affe8c13bcf147c60cdfcb7548aa5c789e981f4872a53ebdda3b841e12f12		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6059 bytes

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