Office (OOXML) / .XLSX malware analysis — malicious · d6369e6a70baba71

MALICIOUS

Office (OOXML) / .XLSX

969.9 KB Created: 2019-11-27 09:20:57 UTC Authoring application: Microsoft Excel 12.0000

MD5: fe87eef0d8e4c05f94d4d0fad743449d SHA-1: c0db768bae2865b7bef56da4f06aa6b7be68bcda SHA-256: d6369e6a70baba71b6309127d7b35cc97de2ef56eb332fc97dfccab24d58a91b

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter

The file is an Office Open XML (OOXML) XLSX document containing an embedded OLE object. Heuristics indicate this OLE object is specifically a Microsoft Equation Editor object that exhibits anomalies consistent with CVE-2018-0798. This vulnerability allows for the execution of arbitrary code, suggesting the embedded object is a payload designed to exploit this flaw. The high entropy and anomalous stream size further support the presence of a malicious payload.

Heuristics 5

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
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` `71710e02f56c79ffef800a563b92a6e099567e54cf9dc5e23f37fd2e65663fb6`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	990720 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` `b4bd80e657c26429480ecd881f5374ee09a8e5c3c49af80d5b150b11d23adc2b`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: olE10naTiVe	980052 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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