Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3555b36d4dc3f989…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:43:29 Authoring application: Microsoft Excel
MD5: 42990fca1e0275fdc24d36fcc7fd7b18 SHA-1: 7ceb0068cad556d20080f95aa402257670a026eb SHA-256: 3555b36d4dc3f989696d68ca977e410a638df340301b752d54436b39c2230e76
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open function. This function is designed to execute arbitrary commands upon opening the workbook, indicating a malicious intent to run code. The presence of dangerous formula APIs further supports the critical heuristic findings.

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
06bb0b66c21b3571473181fdef37c2e74a65ceee9a4107cef0fe7a935cda5813		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6824 bytes

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