Office (OOXML) / .XLSX malware analysis — malicious · 343513fbd6880d9e

MALICIOUS

Office (OOXML) / .XLSX

1.52 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-04-14

MD5: 02642fc503992ccf83d70ae8d856f2dc SHA-1: 50833c2119629f2c305dfe9332ddb7dbe97e4d2e SHA-256: 343513fbd6880d9eb987e5115dc5b3b44dc455635d22c7c1dba38e7bd6beadf1

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The sample is an Excel document containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798 or a similar vulnerability in the Equation Editor to achieve arbitrary code execution.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/db7oeJyTI.u5Pnks 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` `08b0cfb3ad1c6c0dae123b9e544c3f5a9ec07c4917aa57de520ae664fc981ce3`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/db7oeJyTI.u5Pnks	1811968 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` `757717713010cf0065403b0d0f295c57bc93986616d40ca981d46c3cd98d3494`	ole-package	OOXML xl/embeddings/db7oeJyTI.u5Pnks Ole10Native stream: Ole10Native	1795294 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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