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

Static analysis result for SHA-256 507ed4e751689a25…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:26:25 Authoring application: Microsoft Excel
MD5: 19e674c9b91bc1d18be97cae6ab245b9 SHA-1: 7947f6e29d86b6224952cbe3a25e2a684fffae8f SHA-256: 507ed4e751689a2574d1a205f88ff7955408c888e074071cb738acada6a47231
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN further confirms this. The macro sheet is configured to execute automatically upon opening, suggesting it's designed to download and execute a secondary payload. No specific IOCs like URLs or hashes were extracted, but the technique is highly indicative of a downloader or initial access 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
92fff987f9ca04d20a1b54d8a585b4c9a290ba766c7abc359d7da881e4839267
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6623 bytes