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

Static analysis result for SHA-256 19403f2b28f601e6…

MALICIOUS

Office (OOXML) / .XLSX

689.6 KB Created: 2023-10-17 00:12:49 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-10-17
MD5: 24c96da3438b663a9ace920aafe28800 SHA-1: 69b49ade134bcd93df7471e4ef31c00800c6177f SHA-256: 19403f2b28f601e662b3b06bf15dbfd58f3c076443bcefa56da455fff592c194
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1204.002 User Execution: Malicious File

The file is an Office document 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 header and a significantly larger declared inner size than the actual stream size. This strongly suggests exploitation of a known Equation Editor vulnerability to deliver a secondary payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/Fkot6V.kZAx 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
58f7e9f0a745fcf557fc182923629477376783b5c674bb318303331d29abccfb		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/Fkot6V.kZAx 1006592 bytes
ooxml_oleobject_00_ole10native_00.bin
5a30b09c0d52dc143c5f8ac1b96a5feb8eaf5671631ab9c4b4c3f16de288bb0f		 ole-package OOXML xl/embeddings/Fkot6V.kZAx Ole10Native stream: OLE10NaTIve 996290 bytes

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