Office (OOXML) / .XLSX malware analysis — malicious · 8127fb8d2d2bfcae

MALICIOUS

Office (OOXML) / .XLSX

1.57 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-09-16

MD5: f2252590d322c3b63e52cf4e37599819 SHA-1: caec1a0a4b5f6235dd3b177d4b032dee62a440a6 SHA-256: 8127fb8d2d2bfcae79a2c1132cda3fd3b9149fa8b42ac0d1250f3e3a5e57a01e

142 Risk Score

Malware Insights

MITRE ATT&CK

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

The file is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object is anomalous and carries a payload consistent with CVE-2018-0798, a vulnerability affecting Equation Editor. This suggests the document is designed to exploit this vulnerability to execute a malicious payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/TUR2Z1fCu.OaK 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` `c408fc798915d4eadd6cab8831984317399b1a9543b93e999c6f8cb5cce0e237`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/TUR2Z1fCu.OaK	1981440 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` `625bfff6cde38a64f8cfade563aefe35989e7fdffe3b31ed58b14e3e6d51caa0`	ole-package	OOXML xl/embeddings/TUR2Z1fCu.OaK Ole10Native stream: Ole10NatIvE	1963463 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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