Office (OOXML) malware analysis — malicious · f6ea4501bd3e5c26

MALICIOUS

Office (OOXML)

4.35 MB Created: 2021-01-13 03:25:40 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2021-06-17

MD5: aa254ab4401dcf6dc9931b9d7a457c73 SHA-1: cbefc503f8b761eb6a4c990f18ccdc0eff31c630 SHA-256: f6ea4501bd3e5c2682dc17d56ac2cbeb5d5b56cdc2c1062bab4b090633dcee1b

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The file is a malicious Excel document containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object exploits CVE-2018-0798, leveraging an anomalous Equation Editor native stream to deliver a payload. The high entropy and anomalous structure of the embedded stream strongly suggest it contains executable code.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/r9.ZrYho 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`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/r9.ZrYho	4911104 bytes
SHA-256: `b3d658e94d40e1e166036234bacce91a49b321d9544d4fa773f9da165978ac1f`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.92, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin`	ole-package	OOXML xl/embeddings/r9.ZrYho Ole10Native stream: OLE10NATIVE	4870339 bytes
SHA-256: `dbbde55e204180d7fbd8f6db8cafda3c8bd1882f1378cd39bbd1b4ed8db12f74`
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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