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

Static analysis result for SHA-256 728a8824a63aa0bc…

MALICIOUS

Office (OLE) / .XLS

36.5 KB Created: 2020-11-25 10:46:03 Authoring application: Microsoft Excel
MD5: 9f819b2bfe33781d049504b0f6aa1c61 SHA-1: c2a21ea02b8b8fbe98ea7a3a6cdc90348b9195d7 SHA-256: 728a8824a63aa0bcd66180d17a4b65fe6c0ef0bc6deeacf014ebd00700e8c5d4
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 (XLM) macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely downloading and running a secondary payload. No specific family could be identified.

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
49e2c7f9aeac3cf6a5b4bdff8cd70d20aad137a6b925c14ebb359c3d65271106		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6738 bytes

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