Office (OOXML) / .XLSX malware analysis — malicious · 7c26b896ec6d6aee

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: b04726bf46166d1b502c952fc225b6af SHA-1: ea1d8318ba9c4fcce6651eb42342585444b30514 SHA-256: 7c26b896ec6d6aeeb8430321244816edb0910c928a3d2aa086283542a849b364

110 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object carries a payload-like stream with an anomalous header and high entropy, strongly suggesting it's designed to exploit a vulnerability like CVE-2017-11882 for client execution. The presence of hidden sheets further supports the concealment of malicious content.

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 8

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `4ab3e59de609a61e45aed25da58272b33390180d4259716a42d85ab10a7216ac`	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_00_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.
`ooxml_oleobject_01.bin` `e87b7fd9e475e6944f4ee2d39127fc3756bc82e917a196c26a083a0fe1a2e7c9`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	837120 bytes
`ooxml_oleobject_01_ole10native_00.bin` `4eb6f5208d51b555873d392e084629545aaa06c4973181ec27051523a6f931bd`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OLe10NaTIVe	827992 bytes
`ooxml_oleobject_02.bin` `bab38adeb66b87a878bbc8033660dd242c4bbc91b1ecadf8191d37b941408ec2`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject2.bin	1535488 bytes
`ooxml_oleobject_02_ole10native_00.bin` `f7bfcd2cfafe65360c900b06396fb593106749574e01161bc1df7461e65c0804`	ole-package	OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native	1520900 bytes
`emf_00.emf` `072a6a893b25f4848345ae02773b4dd141c43ec598f34f1da6844dabe6ca8a42`	ooxml-emf	OOXML EMF part: xl/media/image2.emf	3042216 bytes
`emf_01.emf` `cd8ade3223da039b578f333c1cac1a6f827c65a4e55a1ed688803ac7cecd7fe2`	ooxml-emf	OOXML EMF part: xl/media/image3.emf	5376 bytes

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