Office (OOXML) / .XLSX malware analysis — malicious · 38d18cd2973bf872

MALICIOUS

Office (OOXML) / .XLSX

224.6 KB Created: 2011-03-22 06:52:17 UTC Authoring application: Microsoft Excel 15.0300

MD5: 6de31ab0b84c12917b6829de119e9083 SHA-1: 95ca1af9a1a06cb6f9484bf06c9b0bf0ffbc532c SHA-256: 38d18cd2973bf872b3baabd7cc323741f8bd0c660bf9cfc91ddbb237f4618005

162 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

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, exploiting CVE-2018-0798. The document body contains a lure instructing the user to 'ENABLE EDITING' to translate language, which is a common tactic to bypass macro security. The embedded OLE object is the primary indicator of malicious intent, likely serving as a dropper for a secondary payload.

Heuristics 6

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/oleObject1.bin 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
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
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` `d1c4bdcfc39872a7c6c24180f4583f4465ee61ae52ad32dcf80961b6274cf2c8`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	220672 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` `83e580134ec135616f485a3be06f822720c0962985e76278ae4b496cf57dcd4e`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OlE10nAtIve	216186 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.

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