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

Static analysis result for SHA-256 a276865b47ec6abe…

MALICIOUS

Office (OOXML) / .XLSX

1.24 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: 38c039eccf5b1f2e55b87c328f2f7f77 SHA-1: 92d27acd36a28a73e4e1fbab13a5f1838ef4a56d SHA-256: a276865b47ec6abead656aac0c862083c8e551218f49a1e6cf98897e4b35dac3
110 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is an OOXML file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. This object exhibits anomalies, including a large declared inner size for its Ole10Native stream, strongly suggesting it carries a malicious payload. The presence of hidden worksheets further supports the concealment of malicious activity. The primary attack vector appears to be the exploitation of a vulnerability within the Equation Editor component.

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
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
    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 9

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
d2817f03b8ec597496e1006a60ae59adfc38b4787aad9d200faddf42a10a4e73		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 799232 bytes
ooxml_oleobject_00_ole10native_00.bin
486f15e937b4f4330ef241fb7a7e96f96b489b173ff1b7b1bc966b6e26f1b3ba		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OLe10NAtivE 790262 bytes
ooxml_oleobject_01.bin
4926d60c10dd395aa1682cc1c15b0d7ce81212ec1649b90cbd89018032fb9772		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 3700224 bytes
ooxml_oleobject_01_ole10native_00.bin
079553d7ab4785a82155c9ad8a77bb8aac84989e54fd6ba4892bc43e2c43717b		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 3668580 bytes
ooxml_oleobject_02.bin
9579f06eaf0a6f3c01267673b63e292e31bf899fac5c84a4be8ca74a6d1bbbd7		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 29696 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.46, consistent with packed or encrypted content.
ooxml_oleobject_02_ole10native_00.bin
d0e65243df358f9ee7948eadb2c9e55da3344dd9a0ee3fcc11d3188c924dc972		 ole-package OOXML xl/embeddings/oleObject3.bin Ole10Native stream: Ole10Native 28007 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.61, consistent with packed or encrypted content.
emf_00.emf
483bccb76820466fffb1bb06d3436d7b79b48f600cca539fd2f514120cd08d78		 ooxml-emf OOXML EMF part: xl/media/image2.emf 7337552 bytes
emf_01.emf
1cf0e2f401f8effed67439dc7b73c481d3bf7f7b25e8cb7686258a5a65691920		 ooxml-emf OOXML EMF part: xl/media/image3.emf 5376 bytes
emf_02.emf
14e680679b0dcfd50e28699e21573be85fe1a53bf52ba5d53c4ef7eaef389fc1		 ooxml-emf OOXML EMF part: xl/media/image4.emf 653280 bytes

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