Office (OOXML) / .XLSX malware analysis — malicious · 70f5c43cd7fa5124

MALICIOUS

Office (OOXML) / .XLSX

1.53 MB Created: 2021-04-28 21:02:36 UTC Authoring application: Microsoft Excel 12.0000

MD5: a55dbbc9061dcb2126f78f5508a4c8ce SHA-1: f621a853d9bb81c3a410e5bc4aff24ff2cb3152f SHA-256: 70f5c43cd7fa51240f496bab1c6a9cf1f67894a0dbe42932346a0184498ad016

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The file is an Excel spreadsheet containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object is anomalous and carries a payload, strongly suggesting exploitation of a known vulnerability like CVE-2018-0798 for client execution. No specific family could be identified, and no further IOCs were extracted.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/rCgOibjh.Sv9S 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` `078de86bd0ebfe61bea301b6303e629aa711f4297b6efa564d00a77908b0beb1`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/rCgOibjh.Sv9S	1837568 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.98, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `b33bc08c15d26a85f144c4fce22ea6915c580ed62f576cbde85140a5592e25a2`	ole-package	OOXML xl/embeddings/rCgOibjh.Sv9S Ole10Native stream: Ole10Native	1820504 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

Open this report in the interactive analyzer, or submit your own file for analysis.