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

Static analysis result for SHA-256 b819f9c54f586043…

MALICIOUS

Office (OLE) / .XLS

323.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: f5448048b5abcb4c79cbe5bec47206ad SHA-1: ea12dc439ad4538d4918da7eb3bd64821680fb4d SHA-256: b819f9c54f58604396698d5ebd93dba9b9319c3941813d7440910892547e2e47
340 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.004 Unix Shell T1105 Ingress Tool Transfer

The file contains both Excel 4.0 (XLM) and VBA macros, with the XLM macro sheet containing an Auto_Open entry. The VBA code explicitly uses URLDownloadToFile to download a file from 'http://listifyapp.co/ds/1612.gif' to 'C:\esiou\'. The presence of 'rundll32.exe DllRegisterServer' in the DOC BODY suggests an attempt to register a downloaded DLL, indicating a downloader or dropper functionality.

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
64441f35e5dd57ce7b24dba58330f10f0d4ac7e777833bfa823d4432a113d1fb		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2148 bytes
macros.bas
2c9bbcb6971a5dd5238f350e10f35a075ce0febf874e7cbf423111bcc0b638e9		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 2049 bytes

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