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

Static analysis result for SHA-256 189a8887d8156233…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:28:05 Authoring application: Microsoft Excel
MD5: a584ec27cd479810a6af73c94c9e0f31 SHA-1: 72d3ac5b391907a41fb1faa22dc4cd05e562d1ab SHA-256: 189a8887d8156233867a2dacf9991749f01cd1387ecc5aa0fc16dcb76d7c5e8c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a critical finding. This indicates the file is designed to automatically execute code upon opening. The presence of dangerous formula APIs like RUN suggests the macro is intended to download and execute a secondary payload, a common technique for 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
f6b45068c4a297383dc3123db3b84014b99dc0c996f06718a3a5fa7324a63dd9		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6519 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.