Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fc94f2b9a29ff958…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:38:17 Authoring application: Microsoft Excel
MD5: dab4c151f849221f03d4794012038c06 SHA-1: f74f8619dac4f83ae7c70f50e7ecd57c1fefad80 SHA-256: fc94f2b9a29ff95803981322cde4e37173baa3b30c706a3df1007772879c0cb4
140 Risk Score

Malware Insights

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros with an Auto_Open entry, which is a common technique for executing malicious code upon opening the document. The macro sheet also contains dangerous formula APIs, specifically a RUN function, suggesting it is designed to execute arbitrary commands. The truncated nature of the macro listing prevents a more detailed analysis of the payload, but the overall pattern points to a macro-based downloader.

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
27ab3efb09dad82105a629ac5e35fd9fcf171ac486ec3d192d791b175b1eab71
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6777 bytes