Office (OOXML) / .XLSX malware analysis — malicious · 93b9bfb13d0cbf3d

MALICIOUS

Office (OOXML) / .XLSX

3.02 MB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-09-20

MD5: 5789abfd18bea68da8d812c35bf46126 SHA-1: 19dffdc8dc7d08f6ec481caec83a98962c633be4 SHA-256: 93b9bfb13d0cbf3d090c27efc0ffac921aac926aab1e99fc574361d1032b4f5c

142 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is an Office Open XML spreadsheet containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. The embedded artifact 'xl/embeddings/p8msSI.7nHm' is the likely carrier of the exploit and subsequent payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/p8msSI.7nHm 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` `19a4337a94e85a9274b592c1cb0a4444241567ecef0640840572065ef976547c`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/p8msSI.7nHm	3431936 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.95, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `ff0994827f91935d3895f77996ad29a52969edf199e3e16fb6e5e7618d07da8a`	ole-package	OOXML xl/embeddings/p8msSI.7nHm Ole10Native stream: oLe10naTiVe	3402625 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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