Office (OOXML) / .XLSX malware analysis — malicious · fc827d0192f306a8

MALICIOUS

Office (OOXML) / .XLSX

1.05 MB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-08-14

MD5: 8596666635944f948a32b4247be77209 SHA-1: 162c543cb26b552e7e283c89dc624cfa9458d929 SHA-256: fc827d0192f306a883a34b6e3a126ee398d98e6bb9b7cd6d549ed3e316d553c9

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The file is an Excel spreadsheet containing an embedded OLE object, specifically identified as a vulnerable Equation Editor component. Heuristics indicate this component is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. The embedded artifact is likely the second-stage payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/v8Lbubqb.2e9 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` `15e174690a169767590a882e6f7b54ec33979846d66e5623b8e55dcd0190f77b`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/v8Lbubqb.2e9	1378816 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.83, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `319071e904640114eb1269e4545ea64900cbe8b80fe9a8d9f946bd5538ec496f`	ole-package	OOXML xl/embeddings/v8Lbubqb.2e9 Ole10Native stream: Ole10NAtIVE	1365416 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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