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

Static analysis result for SHA-256 31936075b0597c1c…

MALICIOUS

Office (OLE) / .XLS

42.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: e9574da2ba8803d698cb7c16d7fc9013 SHA-1: 6b7c021eda16f91714336f1f769ee410365efac5 SHA-256: 31936075b0597c1c7148319a60e90c88dffc3f142cfd69aa40e78c0e89e031ce
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous formula APIs, specifically the 'RUN' function. This suggests the macro is designed to execute arbitrary commands, likely to download and execute a secondary payload. The document body is heavily obfuscated and truncated, providing no clear user-facing lure.

Heuristics 3

  • 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.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
42290f53b0866a5ce70f99bfa4ec02ea5ded37319b160afa4492e620e6c1fcb1		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8197 bytes

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