Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 cb81e443882ed310…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-27 11:38:18 Authoring application: Microsoft Excel
MD5: 3745fdb544048c3a7fef81a081b2cfc2 SHA-1: c0462767fb90b6129ee6033a7b46ff9c94176051 SHA-256: cb81e443882ed31000c2044379a5044aeba8c6dab8b05b553b917c8721c183af
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is an Excel document containing Excel 4.0 (XLM) macros, specifically an Auto_Open function. This function is known to be used to execute malicious code upon opening the document. The presence of dangerous formula APIs within the Auto_Open macro indicates a clear intent to execute arbitrary commands, likely to download and run a secondary payload.

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
33da39c49c3cafe4257487913cb8dcc6c17682401131fde17dd6b9f2278ffb07		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6844 bytes

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