Office (OOXML) / .XLSX malware analysis — malicious · 517acaa0fc12dc40

MALICIOUS

Office (OOXML) / .XLSX

2.17 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000

MD5: 1a5bf5cf28acc0bd2efc2cbc3d0223d3 SHA-1: 5a758e52985fb8de161007083e75d3f251c0bba4 SHA-256: 517acaa0fc12dc40dad4da883fae8767e994614b0e0ed28c9c5792737eba259a

142 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The XLSX file contains an embedded OLE object, specifically an Equation Editor object, which is known to be vulnerable. Heuristics indicate CVE-2018-0798 is likely exploited due to anomalous native stream properties. This suggests the file is designed to leverage this vulnerability to execute a secondary payload, likely delivered via the embedded object.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/GqHqEeqM.9tyRoY 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` `527c25e16ef78f3cbc54a293e2c5512056bdf8cff5e2e4b23c130b74279fd3f9`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/GqHqEeqM.9tyRoY	2563584 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.97, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `ae95e3b79a76c522e671518a11a9e7fda52027c043d9c5225324115491c649e5`	ole-package	OOXML xl/embeddings/GqHqEeqM.9tyRoY Ole10Native stream: Ole10Native	2540560 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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