Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 8e54c73e5b94b6d3…

MALICIOUS

Office (OOXML) / .XLSX

723.3 KB Created: 2010-06-04 08:55:28 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-08-26
MD5: 838c3c96ac0d78f598b90dfa57f4a2a2 SHA-1: 5b976bee3db6f4739ca685f53a98af359b13e3dc SHA-256: 8e54c73e5b94b6d30bcf214dc7dfa9b695b7c5d46d62cd7b0e07acd6a7f1f691
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is an Excel file containing an embedded OLE object, specifically identified as a vulnerable Equation Editor component. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream, suggesting it's being used to exploit a known vulnerability. The large declared inner size compared to the stream size further points to a potential buffer overflow or similar exploit.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/xylobs.XxUFors contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
37cb05e58109cc72084c82cd92f1384060e975f4ea63a69e725204d18c0d0bd1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/xylobs.XxUFors 963584 bytes
ooxml_oleobject_00_ole10native_00.bin
0c0b7f5943429ac6ee65d75231649c8fdf8781cd7627134739f159b5936a2945		 ole-package OOXML xl/embeddings/xylobs.XxUFors Ole10Native stream: olE10NAtIvE 953623 bytes

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