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

Static analysis result for SHA-256 1afee64787f72a56…

MALICIOUS

Office (OOXML) / .XLSX

746.9 KB Created: 2023-01-19 05:24:18 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-04-05
MD5: 37db445b1de71956bad4bf7d5142db3f SHA-1: 0e712061738c8034238b5a577a0afdfb1f2a9186 SHA-256: 1afee64787f72a5625842ed3abfd39e914b34bdc0c08998204dab89f2c404df4
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an Office document containing an embedded OLE object, specifically an Equation Editor. High-severity heuristics indicate this object exploits CVE-2018-0798 due to anomalous native stream data and an impossible Ole10Native header, suggesting it carries a malicious payload. The embedded object's filename and stream name are noted as IOCs.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/FURV.NGgRaaE 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
01c9e00f2ec065e94d4a9f017285b649bb24af51fbc1bbcc9b9bcaba2f1e12d2		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/FURV.NGgRaaE 1076736 bytes
ooxml_oleobject_00_ole10native_00.bin
f6a6d1f1dcbc384b5ddbb736bc1d15cdc4574be7ed8bcbce2c9ee9b38ef6cf7b		 ole-package OOXML xl/embeddings/FURV.NGgRaaE Ole10Native stream: OlE10Native 1065701 bytes

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