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

Static analysis result for SHA-256 b94aa994c9064f2e…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:29:03 Authoring application: Microsoft Excel
MD5: a9054208a4eebf039ff6f223b28f11dd SHA-1: 3170591249aec12c9b7f60ad9af35b6bba89c358 SHA-256: b94aa994c9064f2ecbd3e1c6a2a681a144a4d61d322b38f18836d9e725fc9e33
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 macros, specifically an Auto_Open defined name, which is a critical finding. The presence of dangerous formula APIs like RUN indicates that the macro is designed to execute arbitrary code. This is a common technique for downloading and executing further malicious payloads. No specific family could be identified, but the attack pattern is consistent with macro-based malware delivery.

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
a49259f578a848d687f91c48470a18b975e6b28badebc8c7c1c51fa3d7bfa9f4
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6672 bytes