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

Static analysis result for SHA-256 ca80f8ac9b666116…

MALICIOUS

Office (OOXML) / .XLSX

760.2 KB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000
MD5: 09964d645c84e93e052230f287b33bae SHA-1: 87529d8e0c91efb684356157d46ff066ce8eea33 SHA-256: ca80f8ac9b6661169df31a094a1aad534c8a1ecf4248bd969c88076aff2990f3
140 Risk Score

Malware Insights

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

The sample is an Office document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate the presence of CVE-2018-0798, an anomaly within the Equation Editor's native stream that suggests it carries a payload. This points to exploitation of a vulnerability in the Equation Editor for client execution.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/mFF.Av 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
dd9ce66f4e4ba9b997124b53eb86aea3dbe14c9ad0ed047ea0d32a9183e3f315		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/mFF.Av 1041920 bytes
ooxml_oleobject_00_ole10native_00.bin
516b42c5d098f2d09f3ea5edab7043c56d7a176dd1614d4aade1c1460901ae66		 ole-package OOXML xl/embeddings/mFF.Av Ole10Native stream: oLE10nAtive 1031519 bytes

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