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

Static analysis result for SHA-256 7218eb6faf695f24…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:39:40 Authoring application: Microsoft Excel
MD5: c85b4e215da40fffa3f43893d1d919bd SHA-1: ef4b017e3dc2eea510459066dcddf8ababdf69ed SHA-256: 7218eb6faf695f246dd1529881735aa7ee668d63c891088971fcf6ad39b03c81
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 defined name, which is a critical finding. This indicates the macro sheet is configured to automatically execute code upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands, likely to download and execute a second-stage payload. No specific IOCs like URLs or hashes were extracted from the macro content itself.

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
98a6394a2f516d901a149057ea6c435a805bf2424e788bb8e9025e11cfe70518
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6543 bytes