Office (OOXML) / .XLSX malware analysis — malicious · 1344589e3f12668b

MALICIOUS

Office (OOXML) / .XLSX

1.13 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000

MD5: 2421c4d0fe7f33a7a4a34f3bd57eccac SHA-1: 4e36718f21481b299ad3c10fbccec1ee7dc94fe6 SHA-256: 1344589e3f12668b5e894cb8764d72dd53e39d9e917e090ff7263da64ecbb6b6

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The file is an Excel spreadsheet 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 or a similar vulnerability in the Equation Editor. This allows for client-side code execution.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/Fd4bRp.XIZW 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` `6e29f40d6598565fe90b4c583eed3deb268882fd6d595b089b55bfb3c646b008`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/Fd4bRp.XIZW	1472000 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.73, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `645d382d0a52d0e64d501f8bac0ef3a98339d4d2bd9038fb495f7aec1f97c0e2`	ole-package	OOXML xl/embeddings/Fd4bRp.XIZW Ole10Native stream: ole10nATiVe	1457724 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.73, consistent with packed or encrypted content.

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