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

Static analysis result for SHA-256 b49203aa8da96cd7…

MALICIOUS

Office (OLE) / .XLS

42.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: bdb24e8b4d9c7f1b7f49a4994ae96b25 SHA-1: 2a11ff240a62469a22bb226b234800b161242cb1 SHA-256: b49203aa8da96cd765d5b118040153202e97d5ebd5054f578d57649e9760bc4a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous functions, specifically 'RUN'. This suggests the macro is designed to execute arbitrary commands. The 'RUN' function is a critical indicator of malicious intent, as it can be used to launch executables or scripts. The document body contains heavily obfuscated and truncated text, making it difficult to determine the exact lure, but the macro's functionality points to a downloader or initial execution stage.

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
2d1a379f83358ff9c4f191f6f4de6afe003fbbef1073cec943e0fa0eabea28f6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9015 bytes