Office (OOXML) / .XLSX malware analysis — malicious · e4697f7ffc9eadf4

MALICIOUS

Office (OOXML) / .XLSX

748.2 KB Created: 2019-06-18 09:03:55 UTC Authoring application: Microsoft Excel 16.0300

MD5: 3150e5fb8fbc300badab4bcc4c62ce9e SHA-1: cf017fd5cc8e6ceb6dc575aed5eeabe39ba383cf SHA-256: e4697f7ffc9eadf4f1e783063b84f9c252c2da72c4c56bf32b9a8f162ab5758b

142 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an Office document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. The embedded OLE object's native stream exhibits high entropy and an impossible inner size, confirming its malicious nature. The document body text is minimal and does not provide further context on the lure.

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` `0c382d489d0a697979bae888d7cdfdb3f81c54fbff3c0c5a3e15f0b79c32b554`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	604672 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` `488e0081ee11642a8b60889b5eb80227c76b564a89f347564f499a182e044cdf`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: oLE10NaTive	597006 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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