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

Static analysis result for SHA-256 370d5e6c2737520f…

MALICIOUS

Office (OOXML) / .XLSX

649.6 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-22
MD5: fc72bbb60376284689391c7bc049ea69 SHA-1: 1289ee30677824d1fd895f503986e5856bd2c591 SHA-256: 370d5e6c2737520fcbc77ad8953996afafb597fc01ce132cbd198fd05443b10d
100 Risk Score

Malware Insights

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

The sample is an Excel file containing an embedded OLE object, specifically identified as a Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size difference, strongly suggesting exploitation of a known vulnerability. This pattern is commonly used to deliver second-stage malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/6o2EFkH.MrpU2Ek contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • 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
97e1df275bfe4fbec6c493d63629f1746ace9e372c164ac08e55dcd061df53ac		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/6o2EFkH.MrpU2Ek 911360 bytes
ooxml_oleobject_00_ole10native_00.bin
99377e030265d2973e3f4faea8ec7b78a4881230b7a6ae9678c475589fd9406a		 ole-package OOXML xl/embeddings/6o2EFkH.MrpU2Ek Ole10Native stream: OLE10NaTiVE 902136 bytes

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