Office (OOXML) / .XLSX malware analysis — malicious · f8c0b2be49adcc44

MALICIOUS

Office (OOXML) / .XLSX

623.6 KB Created: 2019-05-27 22:54:04 UTC Authoring application: Microsoft Excel 16.0300

MD5: 77af1d23360aa9cd5a81603412f0ed48 SHA-1: a415fdc8dd07ed195136d19e48f02e15c0ffa6e1 SHA-256: f8c0b2be49adcc44322d5d2c5db13063b9ff30ba751f8a5c5557e5803c3e11fe

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The file contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. The embedded artifact 'ooxml_oleobject_00_ole10native_00.bin' is a high-entropy Ole10Native stream, characteristic of a malicious payload delivery mechanism.

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.
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
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `ab6137e7004003925395e1400d403a3492cd91fecc32e06d327c939d18ac7063`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	636416 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `9488c51abaf28ae147678f48df8bd2da972f81a38f8880fb82d3d5fd0ed205a7`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OlE10NaTIVE	628942 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

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