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

Static analysis result for SHA-256 e8c261ca0a5a7442…

MALICIOUS

Office (OOXML) / .XLSX

858.1 KB Created: 2023-01-19 05:24:18 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-04-04
MD5: 75b376d3162431ddb6468035c2d37a40 SHA-1: 29cbd311dc4b8dec0de5b64d872090618cf82b62 SHA-256: e8c261ca0a5a744211de8ff30047e6efd5c594f47ce8cf2cd1c4f0d3b60f3a8f
140 Risk Score

Malware Insights

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

The sample is an Office Open XML spreadsheet containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object is anomalous and carries a payload-like Ole10Native stream, strongly suggesting exploitation of CVE-2018-0798. This technique is commonly used to download and execute a second-stage payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/8KKlS4.Dhx0dof 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
c007a38625cc384b1cbfe7e31a6d9181920e6ac6859bd68c93ae2c7e73e6fba6		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/8KKlS4.Dhx0dof 1167872 bytes
ooxml_oleobject_00_ole10native_00.bin
e2acb50cc28740e44fb5c53476bf10c528c49cfda24cae60d436a7f32cc12608		 ole-package OOXML xl/embeddings/8KKlS4.Dhx0dof Ole10Native stream: olE10NAtiVE 1156238 bytes

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