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

Static analysis result for SHA-256 1617f1ec2a1aa2f7…

MALICIOUS

Office (OOXML) / .XLSX

2.88 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300
MD5: 1028fc1818673cbe946599bae0b41445 SHA-1: cbc6daf97ef66b58095e06a52962c9bfb680013d SHA-256: 1617f1ec2a1aa2f70f63b2ea38494ecd5374e33b49cfa29a6e1e698a0353187f
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an Excel spreadsheet containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object contains a payload-like Ole10Native stream with an anomalous header, strongly suggesting exploitation of a known vulnerability (e.g., CVE-2017-11882) for client execution. The embedded object's path and stream name are noted as IOCs.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/AA.LHbSt 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
077f38ab24414a1b6f33e42373ba6a3ca2a3dce7bbdd835c2e6aed83ed9233b0		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/AA.LHbSt 2973696 bytes
ooxml_oleobject_00_ole10native_00.bin
d55651bcbf2152b5c1c082cc819d7b4d7f513b8c6df71dd3d036c0af7726307a		 ole-package OOXML xl/embeddings/AA.LHbSt Ole10Native stream: oLE10nAtIVe 2947804 bytes

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