Office (OOXML) / .XLSX malware analysis — malicious · 705a9812b04529ce

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: cda6166fe9c052f024d664bcdc7f0490 SHA-1: 61301459cdf5711310d272e3f1525869ae61b8aa SHA-256: 705a9812b04529ce6ee359e2169efaf5f1fd8a2c98d024ee11c9ca8929ab7b21

152 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file is an Excel document containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. Heuristics indicate anomalies in the native stream of this object, consistent with exploitation of CVE-2018-0798. This suggests the document is designed to exploit this vulnerability to achieve client-side code execution, likely delivered via spearphishing.

Heuristics 7

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/oleObject1.bin 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
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 1 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://www.day.com/dam/1.0
- http://www.w3.org/1999/02/22-rdf-syntax-ns#
- http://ns.adobe.com/tiff/1.0/
- http://purl.org/dc/elements/1.1/

Extracted artifacts 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `5b3e42bb0122b4a8a075b5187014768a3fe8e6a6b510e2bb58740822f001d5b4`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	2120192 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` `f3739e0ec131081816202e0a84ef362010c5e6750524a4d7386d349c2ed5cf07`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: oLE10nATIve	2100846 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.
`ooxml_oleobject_01.bin` `729cfd6013eb7643573c63c7d6571afd4754da3773958943fcde9752273468c0`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/Microsoft_Office_Word_Macro-Enabled_Document1.docm	127551 bytes
`emf_00.emf` `247760a1465ec06870ee453a466118b010b2149730d5dfadb9614dff5e9eae31`	ooxml-emf	OOXML EMF part: xl/media/image5.emf	653280 bytes

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