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

Static analysis result for SHA-256 4b419db35003ca5c…

MALICIOUS

Office (OOXML) / .XLSX

716.0 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2022-03-31
MD5: e8e50c73b4998bfed87b8bbc9eb2036f SHA-1: 3985dbba64d91f27181ba5fe686f2bca425a1b70 SHA-256: 4b419db35003ca5c16bc59ee42b911273da11b25fd5968b4f5765b73256a0b89
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

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 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 the exploitation of a known vulnerability within the Equation Editor component to deliver a secondary malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin 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
ab9864e8e866ad3d9896ca1f36c1687d6dc1d644c7db128f3253de783e13d66f		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 989184 bytes
ooxml_oleobject_00_ole10native_00.bin
0cc94e6ffc97fcb41926ae1953dd3e48a750a99b94fa6bda828af61c5174008b		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OLe10nATIVE 978496 bytes

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