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

Static analysis result for SHA-256 d20d8877e1d1e62d…

MALICIOUS

Office (OLE) / .XLS

45.0 KB Created: 2020-11-05 11:16:40 Authoring application: Microsoft Excel
MD5: 391aa700c2d3f6a4f8cb2627abaf351f SHA-1: c0dc593fa38b644cd08a53b2058a0499009fd23f SHA-256: d20d8877e1d1e62df37b77b9407360cd71db4b5fab218b7bef4d43c47371bbb6
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1566.001 Spearphishing Attachment

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The macro uses the dangerous function 'RUN', suggesting it attempts to execute an arbitrary command or payload. The document body contains obfuscated text, likely to hide the macro's true purpose.

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
fbe6a28c81ccc36055d631a74bb28fafe0a7d2ef2b913a8095f1fb41c2856afd
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 13394 bytes