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

Static analysis result for SHA-256 438133aadb52985f…

MALICIOUS

Office (OOXML) / .XLSX

1.30 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: b6299d44de6b3bb38cc36b0b43f3415f SHA-1: 0d60e51fc0d33c48791fecc49cf09081a2c679bb SHA-256: 438133aadb52985fad58cbd49286f2bcf0fb3d38b36168cd17502be348344644
110 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link T1204.002 Malicious File

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 carries a payload-like Ole10Native stream with an anomalous size, strongly suggesting exploitation of a vulnerability within the Equation Editor. The presence of a hidden worksheet further supports the concealment of malicious content. The primary attack vector is likely the exploitation of the Equation Editor vulnerability to execute a secondary payload.

Heuristics 5

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin 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
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.day.com/dam/1.0
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/tiff/1.0/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
41fb27072790ac5f18e19f41015e6d193d173b38e83d5a60b7a0f5701d1fa94d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 10240 bytes
ooxml_oleobject_00_ole10native_00.bin
59fb77315591a55324873430963abffa12244adc4996302250a87d8a758a5796		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 8667 bytes
ooxml_oleobject_01.bin
bf0885b4e6d7db325ea750591b75e9a052379d2fb35bdef3aecf54abdf3e273e		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 1020928 bytes
ooxml_oleobject_01_ole10native_00.bin
9d66dc0566fbe3eb1d6c2a2d2920fa260fb164f7002c8b707372893c8a5cdeef		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: oLe10native 1010651 bytes
emf_00.emf
745593229286d545d3f60dc77d1bf029af4e6bfe692cd8fbd505d3405280280f		 ooxml-emf OOXML EMF part: xl/media/image10.emf 648132 bytes
emf_01.emf
a4c1cc98a8935f0257ac092374334de7d1048b57a3e1073206b73a150b1c5220		 ooxml-emf OOXML EMF part: xl/media/image11.emf 7608 bytes

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