Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2f4b525677eea1d8…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:37:17 Authoring application: Microsoft Excel
MD5: 83b1393c941a0306f9cff6918ffc6c0c SHA-1: 1acb3be88a81a8410581219636726bd8b81b3344 SHA-256: 2f4b525677eea1d815cac37344ac569e08e2ffded9d37abe8b1b0f65c0b37f36
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a known method for executing malicious code upon opening the document. The macro sheet contains formulas that call dangerous API functions, suggesting it is designed to download and execute 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
a9bef3543514d96760d7866fb88832f4758b5cf52c05c8aef0c94abdfd75f510		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6594 bytes

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