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

Static analysis result for SHA-256 bbe2febe8b665358…

MALICIOUS

Office (OLE) / .XLSX

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-26
MD5: 28ec88f7165c0024d8e842538df48fcd SHA-1: a911d1e81db825c058d80b3716007bb5b9e00d3e SHA-256: bbe2febe8b6653583c2f5a6d690349616c3046a85277be3597b3c3510592a1ec
140 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The `RUN` function within the macro indicates it is designed to execute external commands or download additional payloads. The extracted URLs are likely part of this malicious chain, serving as download locations for further stages of the attack. The presence of the Auto_Open function and the use of the RUN API strongly suggest a downloader or droppper functionality.

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
699e21f010c7c5f5713063f52e691ec519f766e81393f8793f7a585cd43d5349
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7635 bytes