Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2e35de5b5781bfc4…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:55 Authoring application: Microsoft Excel
MD5: fd0c679a54c517fe04b8a6796fb57cf6 SHA-1: 5e52354ece49990dcf771d9fb39d9c6f0031b135 SHA-256: 2e35de5b5781bfc491d24aae6e2597bb71e95bf0f9e7a03ac043e89c1d8e574c
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 macro. This indicates the file is designed to automatically execute code upon opening. The presence of dangerous formula APIs in the Auto_Open macro suggests it is intended to download and execute a secondary payload, a common technique for malware delivery.

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
591160816034cec52e724398280ada549495f191e9a659d72c21ba2e881c825e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6593 bytes

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