Office (OOXML) / .XLSX malware analysis — malicious · 2bf8d828d50a3cf4

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: c8f29d3700e09779bd79f1226ac4bb20 SHA-1: d8fa171c0ff87ed312600e75499a47474c8a8459 SHA-256: 2bf8d828d50a3cf43caad1ed5dc55e5cbb0b02dce62f9be9894d7745c53b576d

170 Risk Score

Malware Insights

MITRE ATT&CK

T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is an Excel file containing an embedded Equation Editor OLE object. Heuristics indicate this object carries a payload-like stream with an anomalous header and high entropy, strongly suggesting it's used for exploitation. ClamAV also detected this file as Win.Malware.Agent-9856821-0, confirming its malicious nature.

Heuristics 6

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.
ClamAV: Win.Malware.Agent-9856821-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Win.Malware.Agent-9856821-0
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` `eed7a5d7a71524ec2465a8230fb7a69a00d180840e3b0a91f354c94ea7211102`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	893440 bytes
`ooxml_oleobject_00_ole10native_00.bin` `cda5bb567b5c448f1e72575b25e52230607131b4c94bb94d82e80ab101c672da`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OLE10NATIvE	883882 bytes
`ooxml_oleobject_01.bin` `c6dcaa2bc919c9a0346280454ccb5471b919293b9c6b8b73cd6f12482001149d`	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` `059cc5c8e7eb2b07f579e2380a808b444f81c0614e8fb75705ec3015e7e93c63`	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` `9157fa2513036e7c7dda70c43bcffd38b71b21953e05185cf824baf5fcb30b58`	ooxml-emf	OOXML EMF part: xl/media/image3.emf	1127736 bytes
`emf_02.emf` `c7af2959f71d820c689b3e19c9cc90d35a9784eddc219042f340189e164a7290`	ooxml-emf	OOXML EMF part: xl/media/image4.emf	5376 bytes

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