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

Static analysis result for SHA-256 c73c28eb08a00d39…

MALICIOUS

Office (OOXML) / .XLSX

606.8 KB Created: 2010-06-04 08:55:28 UTC Authoring application: Microsoft Excel 15.0300
MD5: bac58354a9a3c5445a2bc245018b3606 SHA-1: 78e3dcddeecf41a19e785234d8de0de7d2e34105 SHA-256: c73c28eb08a00d399f26b66a7df488c3005fbe6cfb93a1bbeb1637249ac81832
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file contains an embedded OLE object, specifically identified as a vulnerable Equation Editor object. Heuristics indicate anomalies in the native stream consistent with CVE-2018-0798, suggesting it's designed to exploit this vulnerability. The embedded object's native stream is highly anomalous and appears to carry a payload, likely for client-side execution. No scripts were extracted, and the document body content is unrelated to the malicious functionality.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/hDV1U.YeVyE 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
3495b5316d96fcd90929bda42a1ab1323494b55d206a52ed60e4d87ac7965ca3		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/hDV1U.YeVyE 801792 bytes
ooxml_oleobject_00_ole10native_00.bin
2bd84628f666a2c351d0993981716749dd8e37795c0f972759e84d9833f29263		 ole-package OOXML xl/embeddings/hDV1U.YeVyE Ole10Native stream: olE10NATivE 792870 bytes

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