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

Static analysis result for SHA-256 73f94f60b000264f…

MALICIOUS

Office (OOXML) / .XLSX

2.14 MB Created: 2025-07-15 00:56:42 UTC Authoring application: Microsoft Excel 12.0000
MD5: 629da9978d4bd4840688d029e85c53e8 SHA-1: 79c84c08a59fb6dc29dffb508d085bb7804e2303 SHA-256: 73f94f60b000264f4888d7ec76a30d17459b3fa423e76217a918b0da8ef9a7bf
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample contains an embedded Equation Editor OLE object with an anomalous Ole10Native stream, indicating it likely exploits a vulnerability such as CVE-2017-11882 for client execution. The presence of this object strongly suggests the document is designed to deliver a secondary payload upon opening. The document body content is garbled and does not provide further context.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/FN5A09.pAaC8gz 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
b4fedb3ecba9dba760dc2bfd6a926bcafb58e2e7af46c9a366b410dd3f26ea91		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/FN5A09.pAaC8gz 2998272 bytes
ooxml_oleobject_00_ole10native_00.bin
caebbd73d94e2b44345fdac4d972ea5a8df0fa8c7f05f8e22ea834b0d97ef33c		 ole-package OOXML xl/embeddings/FN5A09.pAaC8gz Ole10Native stream: OlE10natIVe 2972228 bytes

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