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

Static analysis result for SHA-256 15b80e3b4c0b1812…

MALICIOUS

Office (OLE) / .XLS

41.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: d873dcc454f292a5d8d92a181472fc8f SHA-1: d6fc9189bd910a0a12933996dedb3896d53fb9ee SHA-256: 15b80e3b4c0b1812bdc03f5f55cdef6fff090ac31998f4c329ebfecb3f27d1d4
140 Risk Score

Malware Insights

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

The file is an Excel XLS document containing Excel 4.0 macros. The presence of an Auto_Open defined name and the use of dangerous formula APIs indicate that the macro is designed to execute automatically upon opening. This mechanism is commonly used to download and execute a secondary payload, hence the classification as an exploitation for client execution.

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
090c2de26dd42678730afb1c6f961b4cd001f8f3cf1784f579439dc26bd1c784		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7902 bytes

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