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

Static analysis result for SHA-256 d2d829ca93afa71c…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-30 17:55:08 Authoring application: Microsoft Excel
MD5: a9eab970ea7c70eb180671005155582d SHA-1: cef8de1a8923313e65f2dd8cf5d00c5a10bf0c9a SHA-256: d2d829ca93afa71cbe24762b562f6079e2e1d4082e166c7181e198a4c8da32c5
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates that the macro will execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands. While no specific URLs or hashes were extracted, the Auto_Open macro itself is the primary indicator of malicious intent, likely serving as a downloader or initial execution vector.

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
52da598c2f738b176b715e890b8ecce764173d03c10b28126959da6f24887ce2
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6485 bytes