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

Static analysis result for SHA-256 dbae6d49f448a98b…

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 9d87250f18de736be5a0f1277e451762 SHA-1: 7ab740530148453e28c9010b3dd93de86cdfca7b SHA-256: dbae6d49f448a98b486198254c31102bf176dfae79fb5f4799e8c0b1f4a0b71b
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs, specifically 'RUN'. This strongly suggests the macro is designed to automatically execute code upon opening. The 'RUN' function in XLM macros is typically used to launch external executables or scripts, implying a downloader or initial execution vector. No specific family could be identified, but the technique is common for initial access.

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
454f61eb0107f937a2b4eb1a8663f007d4b4eee4e3e170de740b026ee53f0213
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8274 bytes