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

Static analysis result for SHA-256 a387ea45fdee5714…

MALICIOUS

Office (OOXML) / .XLSX

677.0 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-09-12
MD5: 71f5fa719f6cf50bc61c44903cf18416 SHA-1: 6af93bc72e8471327422a03630d2da463326fee4 SHA-256: a387ea45fdee5714719aa996efec435fa969b96c2d91631e780ef01609e13eca
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. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header, suggesting it is designed to exploit a vulnerability. This is a common delivery mechanism for malware, often initiated via spearphishing attachments.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/fx7.Netduj 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
bf7e04030361139c5e7303e907720535a53a69a41434f7bfd4a4d53d4339cb02		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/fx7.Netduj 989184 bytes
ooxml_oleobject_00_ole10native_00.bin
0bcada652aac492cbfe4595848588dad3a0ba47b27c04bcf89921095260a210d		 ole-package OOXML xl/embeddings/fx7.Netduj Ole10Native stream: Ole10NATiVE 978456 bytes

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