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

Static analysis result for SHA-256 e7ffe2f6ef080f4d…

MALICIOUS

Office (OOXML) / .XLSX

940.6 KB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000
MD5: e228a9a207ec66fb124662f5e54400e7 SHA-1: 4ea40cbeedc4ec6cdf1735e2a5cce93cb8defd86 SHA-256: e7ffe2f6ef080f4db1e604709294a85c4181395897e493ddfe898e810ea3d253
140 Risk Score

Malware Insights

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

The file is an Office document containing an embedded OLE object, specifically identified as an Equation Editor object. High-severity heuristics indicate that this Equation Editor object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. This technique is commonly used to deliver second-stage malware. The embedded OLE object's path is xl/embeddings/k8K.Sp5oyj.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/k8K.Sp5oyj 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
b0a4f340e7f35a76289880a3f090c3ffe75f31887e5bf66261877dec450eba33		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/k8K.Sp5oyj 1245184 bytes
ooxml_oleobject_00_ole10native_00.bin
bcf3a458902f9f517720e8a1a1d032dbc9baae4b529453195d0f79a6ebaa26d7		 ole-package OOXML xl/embeddings/k8K.Sp5oyj Ole10Native stream: OLe10NAtIVe 1233056 bytes

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