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

Static analysis result for SHA-256 89158019cf17def4…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:37:47 Authoring application: Microsoft Excel
MD5: 367659c2ceb6f9536e84e8e9c1d3825e SHA-1: fc3dc3773bfcd6161ca64bda3727332507783142 SHA-256: 89158019cf17def41ee5f15cd816a0dae3914ccd460df678f5634c82ae2394ec
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates 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 external commands or download and run a second-stage payload. No specific URLs or hashes were extracted, but the technique itself is highly indicative of malicious intent.

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
86301160b683c9b891e9a85c6cd18d30c8ae5e6665e02020e37f077690558083
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6651 bytes