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

Static analysis result for SHA-256 639f6453e961aa33…

MALICIOUS

Office (OOXML) / .XLSX

1.17 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: 64dbb078907cdeb6e76ce5b8a21bb98a SHA-1: 7a86be09afd55c1581a416ad9f948798540fe5e2 SHA-256: 639f6453e961aa33302d34962ccdd29fbc9235b2a0df8b1ac0acc0bb040af7e0
110 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

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 this object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the actual stream size, strongly suggesting exploitation of a vulnerability within the Equation Editor. This type of exploit typically leads to arbitrary code execution.

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 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
165213bd9c2454af97bb6867629bcf6808aa2db3b3609398e06a086b596249ff		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 867328 bytes
ooxml_oleobject_00_ole10native_00.bin
c64178bac9f6faa9af16be3cb40aa8f640e5dec567dc52fa5a3cf1a520b288b1		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: olE10NAtIVE 857670 bytes
ooxml_oleobject_01.bin
3b2bd5ac769197d3c20fc58372032236a445090ea1e6cdbaaed2e62ae93316a1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 32768 bytes
ooxml_oleobject_01_ole10native_00.bin
d99c4f7b75c5d87127e2729121a439c1a52b946b0accab53494d8313bb27bd81		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 30925 bytes
ooxml_oleobject_02.bin
da169d49d0fa7a522e4452305e265f4d087e137c333d65ca5f5f6fbed76a5948		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/Microsoft_Office_Word_Macro-Enabled_Document1.docm 122622 bytes
emf_00.emf
8fe33aff47c6c1c682df04cfbfc7c1373ae6353c3ceb9c070663d0dd7d8d98ad		 ooxml-emf OOXML EMF part: xl/media/image9.emf 1183280 bytes
emf_01.emf
0817a1740e49c41c86dfca303f516f04277cf036751114f1849b608bf4981c81		 ooxml-emf OOXML EMF part: xl/media/image10.emf 7592 bytes

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