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

Static analysis result for SHA-256 903393637510ba1a…

MALICIOUS

Office (OOXML) / .XLSX

739.7 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-09-12
MD5: 25e5833b3a562cf69a671559a7e9e187 SHA-1: 10580b3e9fe6726588e12b4842c35c90d962d9ff SHA-256: 903393637510ba1a9ed321520c1d1d73f8bd559cf926f3afb72c298df1ee6e8c
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 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. Heuristics indicate that this Equation Editor object carries an anomalous Ole10Native stream, suggesting it is being used to deliver a secondary payload. The presence of an embedded OLE object and the anomalous Ole10Native stream strongly indicate an exploit targeting the Equation Editor vulnerability, likely for initial execution of a malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/fxWXYk8zW.bQ 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
314bf30651d3b56a64de6ee9e9c7fbbb24d02c3f766ae4b96f1157d7f9dddf3d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/fxWXYk8zW.bQ 1102848 bytes
ooxml_oleobject_00_ole10native_00.bin
ce6f42a5ef6968a86b6a379689ee7466af6e9250e0ca1957c7e537e15933750e		 ole-package OOXML xl/embeddings/fxWXYk8zW.bQ Ole10Native stream: Ole10nativE 1091843 bytes

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