Office (OOXML) / .XLSX malware analysis — malicious · bb4fa6b491fd2970

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 315910d850e31bc5690c383c800beb19 SHA-1: 1c9eb41a7e7b396b3e2f88cd0b1a971800be27d9 SHA-256: bb4fa6b491fd297062c2930b84d385ab85eaf1dd68b57a08f2e44e6300cb5b9e

150 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this object is anomalous and likely exploits CVE-2018-0798, carrying a payload within its Ole10Native stream. This suggests the file is designed to execute arbitrary code upon opening by leveraging a vulnerability in the Equation Editor component.

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.
CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY

Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
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 5

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `3e7ca3d16d83f57a46e3ef5133fb9a805cdc239975d616c4521afb5269835f01`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject2.bin	1614848 bytes
`ooxml_oleobject_00_ole10native_00.bin` `ae6173ee54937f64c652977a63ceeb27438c18c8874634ccf808a82e16b09e02`	ole-package	OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native	1599780 bytes
`ooxml_oleobject_01.bin` `b0661c520a96e86df446370de18cb5be8f55acc0d528b02cf39c6655bd2ac686`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	1758720 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.98, consistent with packed or encrypted content.
`ooxml_oleobject_01_ole10native_00.bin` `17a4ab46fc8bb16c8c9fc6366858ee3ecdbdd4001d9266b60402934a24c0ac62`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: ole10NaTivE	1742446 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.
`emf_00.emf` `5ec13fdb116fad2a722159ac55f98a857e0925759bcaeb75ac83fccbf7c3e8c2`	ooxml-emf	OOXML EMF part: xl/media/image8.emf	3199944 bytes

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