Office (OOXML) / .XLSX malware analysis — malicious · da22b925942c0e3b

MALICIOUS

Office (OOXML) / .XLSX

1.30 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-04-13

MD5: 41e6ae8455f51f843054c2c3cff024c8 SHA-1: 821c3a619af90b1e228a801b378ee133a5b2cdae SHA-256: da22b925942c0e3b3f5deb4e5661a2c0ac8fa5902b06053ee58e3c53ec3bedb5

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1027 Obfuscated Files or Information

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object is anomalous and carries a payload-like stream, strongly suggesting exploitation of CVE-2018-0798. This technique is commonly used to execute arbitrary code. The embedded artifact 'ooxml_oleobject_00_ole10native_00.bin' is likely the delivered payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/PuH.uV 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` `a3fa7ce7631c9160336996423d82e835dac53e14573b350b5410ce22e908dcf3`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/PuH.uV	1593856 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` `334d57613ff533e2e722c15a966a5a5f97e013aefd6b5aa1b69c6fab71ac2a76`	ole-package	OOXML xl/embeddings/PuH.uV Ole10Native stream: Ole10Native	1578637 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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