Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ac6925d7c538ed93…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:44:57 Authoring application: Microsoft Excel
MD5: 95a5530cef9155fb8ba500808fb05f03 SHA-1: a265ae64d643ebdd14d116e3c2c082c3ca1d0377 SHA-256: ac6925d7c538ed93c862ac5347ecc37a5380cd7d3d25bb3cbc7ebba28402be35
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 common technique for executing malicious code upon opening the document. The macro sheet contains references to dangerous formula APIs like RUN, suggesting it's designed to download and execute a second-stage payload. The extensive obfuscated strings in the DOC BODY further support the malicious intent.

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
830d875c40995de3943df45bd07615278e82cfb5ffc965ccf2e1ae6dfbac0e5b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6357 bytes

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