Office (OOXML) / .XLSX malware analysis — malicious · 8eae2db67186a7ff

MALICIOUS

Office (OOXML) / .XLSX

1.27 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-06-15

MD5: d44a73e329df0e62775cf68958efa1f0 SHA-1: 74de746e4295140d7305eb72902dd942b3f1d63d SHA-256: 8eae2db67186a7ff3940b8723d458b453914c0c97af9fde570fcf816b3ae2b24

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious File T1204.002 Malicious File: Exploitation for Defense Evasion T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The file is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object exploits CVE-2018-0798, a vulnerability in the Equation Editor. The object's Ole10Native stream is anomalous and exhibits high entropy, suggesting it carries a malicious payload. The embedded artifact 'xl/embeddings/nk1U7EJYK.9au' is the likely carrier of this exploit.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/nk1U7EJYK.9au 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` `0249b311d190556eeb7410d5ec13f6d03befba0a20a1bd8223be6a233cf3bb3f`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/nk1U7EJYK.9au	1627136 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `a1279b8e47c38bf232e376505ece081064ecb515107ce130ed0ed43ff0a1db93`	ole-package	OOXML xl/embeddings/nk1U7EJYK.9au Ole10Native stream: ole10NAtIVE	1612062 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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