Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c9f437afe3c6d98b…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:39:58 Authoring application: Microsoft Excel
MD5: 9c8a8cd3ee03c13d95ba4170d81db214 SHA-1: 64650b9f9ddfe7157a7da03d4e982cf64fc89945 SHA-256: c9f437afe3c6d98b1c1e70a2d1e05b8a733c07bedc56e118c2ba9b7f13c274b4
140 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The presence of an Auto_Open defined name suggests that the macro will execute automatically upon opening the workbook. The dangerous formula API 'RUN' (risky-formula=3) is present, which is commonly used to execute arbitrary commands or download and run malicious payloads. No specific URLs or hashes were extracted, but the technique strongly implies a downloader or initial execution stage.

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
6e4c27d9b657431685e5479c8aea4fee8bc8f600fd694d36242eba4b8363555f
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6363 bytes