Office (OOXML) / .XLSX malware analysis — malicious · fd61bc6bafc3fac0

MALICIOUS

Office (OOXML) / .XLSX

1.89 MB Created: 2022-11-18 02:05:27 UTC Authoring application: Microsoft Excel 12.0000

MD5: f5b33e74df0526be97d3bad98db41da7 SHA-1: 69befdb163ca1bf846ec84b1f4c84588666727ff SHA-256: fd61bc6bafc3fac09b4c9fab5d1d32358eb263167adaa3275427f20a55902a9f

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious File T1559 Component Object Model Hijacking

The file is an Excel document containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. Heuristics indicate anomalies within the Equation Editor's native stream, strongly suggesting it's being used to deliver a malicious payload, likely exploiting CVE-2018-0798. The embedded object and its associated streams are the primary indicators of compromise.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/nMM.FBY6 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` `0316fc7257f837d0035dbe6a9005f67550222b9b992393631a0c21eb975d9753`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/nMM.FBY6	2283520 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.98, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `925a2cd3691142d3b637853f67278b8b259f5c74a472758962a86cdc05710b39`	ole-package	OOXML xl/embeddings/nMM.FBY6 Ole10Native stream: ole10naTIVe	2263290 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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