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

Static analysis result for SHA-256 39c36673d8e2614b…

MALICIOUS

Office (OOXML) / .XLSX

646.2 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-07
MD5: 0db2561abccbaa507fb524738498a103 SHA-1: 67b29c36c6dc0fcdc9981352d3e43841ef54e61e SHA-256: 39c36673d8e2614bf03861db0c762c6753a848e30a7f4c86245a907aad5e4d2b
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 Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and size discrepancy, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This indicates the file is designed to exploit this vulnerability upon opening to deliver a secondary malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/WjIixyDJO.cicbxfC 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
8a114632619198bee0d49c93a69baa87e2a480e536cbad1f902397413b2366a2		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/WjIixyDJO.cicbxfC 890368 bytes
ooxml_oleobject_00_ole10native_00.bin
ff069ebd14017e7159ffb7cfe1bbe87c3c4e60c0e66a82524f381f3da6fa418a		 ole-package OOXML xl/embeddings/WjIixyDJO.cicbxfC Ole10Native stream: oLE10NatIvE 881125 bytes

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