Office (OOXML) / .XLSX malware analysis — malicious · 758babb4a9a5fe4b

MALICIOUS

Office (OOXML) / .XLSX

873.6 KB Created: 2023-01-19 05:24:18 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-02-20

MD5: 822e04d01976758fde626715bc7088a2 SHA-1: a5207fd96dc218a708320e10e4a5d80a015c9ec3 SHA-256: 758babb4a9a5fe4b8c01249407865b66d21151853ef0d89cbcdb5c4094381c27

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 vulnerable Equation Editor object. Heuristics indicate anomalies consistent with CVE-2018-0798, suggesting the Equation Editor object is used to deliver a payload. The embedded OLE object and its native stream are flagged as suspicious due to high entropy and size discrepancies, pointing towards exploitation for client execution.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/EnAagSNdp.U6EBiZd 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` `b26badedfd08a1b37f277594461c8c430c9f24375dcb0d973945a07c58045944`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/EnAagSNdp.U6EBiZd	1133568 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.42, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `807d3816692b7f8b1f28cabb441cefb17b53a085571f592fb84e662eb2507a6d`	ole-package	OOXML xl/embeddings/EnAagSNdp.U6EBiZd Ole10Native stream: oLe10NaTivE	1122057 bytes

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