Office (OOXML) / .XLSX malware analysis — malicious · 6b33c07dace9e71e

MALICIOUS

Office (OOXML) / .XLSX

1.19 MB Created: 2022-11-18 02:05:27 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-04-01

MD5: 6971f4c7a19776526019968f4affc2d5 SHA-1: 354dc5550ddceba7961d56e640258a656be72d75 SHA-256: 6b33c07dace9e71ed184d8957a488e3ca72ab5422db0786f0282c1bdabd8a718

142 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an OOXML 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. The embedded object is likely responsible for delivering a second-stage malicious payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/uFVXyIp.otu 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` `016d250a1711eac64029e550988234bd1c20f7915bbdf364c315e782e910be9c`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/uFVXyIp.otu	1548800 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` `c6db6f51253d50efb912df850a2d27d796218d0cfc3e64db90da2fdb7a1b9a84`	ole-package	OOXML xl/embeddings/uFVXyIp.otu Ole10Native stream: OLE10naTiVe	1534360 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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