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

Static analysis result for SHA-256 c8381037a439cb72…

MALICIOUS

Office (OOXML) / .XLSX

814.5 KB Created: 2023-01-19 05:24:18 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-03-24
MD5: 0b21432118ee771920b7ea1ab0291a6b SHA-1: ab7fbfe7ac70726729f2ee75468833f5a3eaff5a SHA-256: c8381037a439cb72f8927b7f13c5007d8ac1e7964d9f7c98540227e5aae68805
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The sample is an Excel file containing an embedded OLE object, specifically targeting a vulnerability in the Equation Editor (CVE-2018-0798). The Ole10Native stream within this object exhibits anomalies and a high entropy payload, strongly indicating it's designed to execute arbitrary code. This points to a classic exploit delivery mechanism for client-side execution.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/RyyuE5Y.Yi2R09l contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • 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
4abfc195491b49b8b800d33e8462c64629379646c710c5019b26bbff3c28e38b		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/RyyuE5Y.Yi2R09l 1072640 bytes
ooxml_oleobject_00_ole10native_00.bin
0208af4491f0c02c649a34e93d66a6c611669d875c78a8d41d3044f22b5c8aa2		 ole-package OOXML xl/embeddings/RyyuE5Y.Yi2R09l Ole10Native stream: oLe10NaTiVE 1061534 bytes

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