Office (OOXML) / .XLSX malware analysis — malicious · bc49a8d949163802

MALICIOUS

Office (OOXML) / .XLSX

1.44 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000

MD5: b0acb4945db74ef13b18c1a070e23199 SHA-1: 0e892062df26a3f14bc88d79ebc7fd8ecddc5009 SHA-256: bc49a8d949163802d2b46f08a0998a39376cc5bde24377c4d40e11b8bc4e2409

110 Risk Score

Malware Insights

MITRE ATT&CK

T1559.001 Component Object Model T1204.002 Malicious File

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the actual stream size. This suggests an attempt to exploit a vulnerability within the Equation Editor component to execute arbitrary code.

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.

Extracted artifacts 9

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `4ee28dc49ddb04515bac910ca6ea58c0009131d33a3cb35f54aa9f0ae909b186`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	1070080 bytes
`ooxml_oleobject_00_ole10native_00.bin` `fa26266672651d2aa6f84bae7b90d6bc3df77c48d34c9c6ff22a00516728bc47`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: olE10NAtIve	1059205 bytes
`ooxml_oleobject_01.bin` `693c97cca80cf68eeeb5777d50244fb5c7ce395aec0454d9f0a03098fadfe851`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject2.bin	1535488 bytes
`ooxml_oleobject_01_ole10native_00.bin` `f7bfcd2cfafe65360c900b06396fb593106749574e01161bc1df7461e65c0804`	ole-package	OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native	1520900 bytes
`ooxml_oleobject_02.bin` `02811a74b85ae2975163dc718180dbc9a721b69db9f9efa973e6a5e49aa65a15`	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` `072a6a893b25f4848345ae02773b4dd141c43ec598f34f1da6844dabe6ca8a42`	ooxml-emf	OOXML EMF part: xl/media/image2.emf	3042216 bytes
`emf_01.emf` `c3b4856ec70f52233191a4286960339ebc355a5fe3021bd5d6040893095eaf0e`	ooxml-emf	OOXML EMF part: xl/media/image3.emf	1127736 bytes
`emf_02.emf` `2e5e79d792b664c65c69f30b170f7208964381b3b0d638cac90e6ad992c3ccae`	ooxml-emf	OOXML EMF part: xl/media/image4.emf	5376 bytes

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