Office (OOXML) / .XLSX malware analysis — malicious · 9236e76f0921e7ac

MALICIOUS

Office (OOXML) / .XLSX

1.22 MB Created: 2021-08-09 02:12:21 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-09-07

MD5: dac339ced4b038612a71010f9191029f SHA-1: 85b1f5f307d424ef05c762710ca038b07ff7f04a SHA-256: 9236e76f0921e7ac64e9d8496fb6a694da04b77cfe3d9e594709533f25f8dcb6

142 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an Excel document 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 likely carries a malicious payload, exploiting CVE-2018-0798. The embedded artifacts suggest the presence of a second-stage payload. The attack pattern is consistent with exploiting a known vulnerability via a malicious document attachment.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/iXH1j.F9Z9Lgl 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` `214c2ffe0d3153c3f6b6af90db8c6743968b7af4569a76eff4681d389399a10e`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/iXH1j.F9Z9Lgl	1501696 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` `3eb874dc580468851eb78f86d4e2c468949145cecfbaa05c0e627ad810dba758`	ole-package	OOXML xl/embeddings/iXH1j.F9Z9Lgl Ole10Native stream: oLe10natIVE	1487736 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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