Office (OOXML) / .XLSX malware analysis — malicious · 4f2890801a7e8aec

MALICIOUS

Office (OOXML) / .XLSX

1.58 MB Created: 2022-11-18 02:05:27 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2024-07-10

MD5: 43833393b399b9c3ffb3fa54dddf70ce SHA-1: 63b2403b6ca0ecdb75645ff24fba5f7c69a0706a SHA-256: 4f2890801a7e8aecd34c4dcdf0767614335a8de5645798d23bbc4f209f46843a

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious File T1204.002 Malicious File: User Execution T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: COM Hijacking

The file is an Office Open XML (OOXML) document containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. Heuristics indicate exploitation of CVE-2018-0798, which is known to deliver a second-stage payload. The embedded OLE object's native stream exhibits anomalies consistent with a malicious payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/kGxrCI1TC.3Lw1Y 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` `cd75bfe80c767358e92dc5004342e05ff519e8932f21becdd43b589bdb434eb7`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/kGxrCI1TC.3Lw1Y	1932288 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.98, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `30c6d8c91a9d3f74b438b7ae848c5323b90288994aa3982d2f6ca6e9541d0d05`	ole-package	OOXML xl/embeddings/kGxrCI1TC.3Lw1Y Ole10Native stream: oLE10nAtIvE	1914514 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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