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

Static analysis result for SHA-256 f73577433746d6b2…

MALICIOUS

Office (OOXML) / .XLSX

719.0 KB Created: 2022-08-10 18:51:50 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-10-17
MD5: 43f6a3400d70a7b87a482333ee864411 SHA-1: d6152f4bccda94cdfe4661c5b935a715634199b1 SHA-256: f73577433746d6b20849bce8f29d8be665c3ac284af3c41d0007eb8803d2eb75
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The file is an OOXML document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like stream with an anomalous header and a significantly larger declared inner size than the actual stream size, strongly suggesting exploitation of a vulnerability like CVE-2017-11882. This technique is commonly used to download and execute a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/XnS.106U 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
1d6506dc610a9b4e0333dc94c2a0f36ba828f1c6041a277e65841823b04c22ef		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/XnS.106U 1016320 bytes
ooxml_oleobject_00_ole10native_00.bin
43fcb9fbccd7320224fc07ef1c0d7faf885dd1042937a3463155c449f37a6b94		 ole-package OOXML xl/embeddings/XnS.106U Ole10Native stream: Ole10nAtIVe 1005874 bytes

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