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

Static analysis result for SHA-256 9f50bac35f7e909d…

MALICIOUS

Office (OLE) / .XLS

326.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 86f80b83ac388d929a837f34573280c4 SHA-1: f634ef80b00cdcd7c77b54c1bd20b9c464fda71f SHA-256: 9f50bac35f7e909dc8f754e278667973b3fd91261b7ab0b9d1aa9afe7bac26b7
340 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1105 Ingress Tool Transfer

The file contains both Excel 4.0 macros and VBA code. The VBA macro 'Viurni' explicitly calls URLDownloadToFile to download a file from 'http://catalysticmedia.com/ds/2112.gif' and saves it to a path derived from 'Sheets("Doc2").Range("AH7")'. The Excel 4.0 macros also contain references to dangerous functions like RUN and EXEC, and an Auto_Open entry, indicating an attempt to execute code upon opening. The presence of 'DocuSign' in sheet names and the DOC BODY suggests a lure related to document signing.

Heuristics 7

  • 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.
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in 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.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
52ac84983ea537f13ec7e38300a206c002917bfa7200ec809f51e73b54e041b8		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1674 bytes
macros.bas
53d1a672c81b94e0436a54beda273f5769c7489beb41e537659c06874369a41c		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 2189 bytes

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