Office (OOXML) / .XLSX malware analysis — malicious · 2044524fe88a8ed1

MALICIOUS

Office (OOXML) / .XLSX

1.98 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-03-05

MD5: 672a4cb0339039cd0f3b056de73800fa SHA-1: 6f6ab0cd96eed0246f883e97461539c52e2328f8 SHA-256: 2044524fe88a8ed1ea1d5428cba427f87763e35ed487d91fe5c1bef12a6d26df

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious File T1559 Component Object Model Hijacking

The sample is an Excel file containing an embedded OLE object, specifically identified as a malicious Equation Editor object. Heuristics indicate the presence of CVE-2018-0798, an anomaly in the Equation Editor's native stream, and a high-entropy payload within the Ole10Native stream. This strongly suggests the file is designed to exploit this vulnerability to execute a secondary payload, likely embedded within the Ole10Native stream.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/rtaL0uQT2.Lfl0 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` `265be39fc359843e540203ec5a666e0ed42f2fe1768c27176991ac05c673e960`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/rtaL0uQT2.Lfl0	2351616 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` `6c4c7bd07d4a1bb828de14419cd72c1eb80da337d2e03c83e67515b58f67b763`	ole-package	OOXML xl/embeddings/rtaL0uQT2.Lfl0 Ole10Native stream: Ole10Native	2330672 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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