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

Static analysis result for SHA-256 d0cbfc1ea7fa85ad…

MALICIOUS

Office (OLE) / .XLS

36.5 KB Created: 2020-11-30 11:06:47 Authoring application: Microsoft Excel
MD5: c5940fff1320830d71f29fb2690b8f35 SHA-1: 03e1abc68ef62682ceb5c6febe2da4019c9c2cfd SHA-256: d0cbfc1ea7fa85ad1405d264b0105f3a4cb94e6fe8767ccf19cac61d615d166c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell 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 known technique for executing malicious code upon opening the document. The macro sheet contains a defined name 'Auto_Open' and uses dangerous formula APIs, specifically the RUN function, indicating it's designed to execute arbitrary commands. The document body contains obfuscated text, likely part of the lure or payload. The presence of an Auto_Open function strongly suggests an attack pattern focused on initial execution via a malicious attachment.

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
7334a2290698cd54a779c568ea4617df3b411aeea1d37dc0da2ed70c9121e5fe
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6574 bytes