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

Static analysis result for SHA-256 833a874624b92707…

MALICIOUS

Office (OOXML) / .XLSX

610.6 KB Created: 2024-03-25 10:30:17 UTC Authoring application: Microsoft Excel 12.0000
MD5: 7c5a6fd0cbae7b269ec59ddcdc23522d SHA-1: 2bdd3d033d80ffc1551e5723a09774e67556a5dc SHA-256: 833a874624b92707d7047183463fe640552c93cec6536ef5725879b981475338
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an Excel file 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 structure and the anomalous stream size point to the execution of arbitrary code.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/lC1.EPgQ 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
1024d7a7f925af74facf9de054f4b0c06845f3b8380e7157d25299ccde71c45a		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/lC1.EPgQ 905216 bytes
ooxml_oleobject_00_ole10native_00.bin
a6d20c1436caee30e6dd835b55ce8ca53614e9b742a73049590e6b888548e732		 ole-package OOXML xl/embeddings/lC1.EPgQ Ole10Native stream: OLE10NAtive 895767 bytes

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