Office (OOXML) / .XLSX malware analysis — malicious · c07a88c06fcb1efd

MALICIOUS

Office (OOXML) / .XLSX

1.10 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-06-23

MD5: 2f4af6425922f0266acb56689c0f6db9 SHA-1: 8038956c747fe326d14280ec636e82a41bf5dea1 SHA-256: c07a88c06fcb1efdec2275c9e3fdad322622c8b908e79e45de9bad6f78da9f01

142 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is an Office Open XML (XLSX) file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object exploits CVE-2018-0798 by leveraging an anomalous Equation Editor native stream with high entropy, suggesting it carries a malicious payload. The embedded artifact 'xl/embeddings/L7cIdc7.SrfqPgK' is the likely carrier of this exploit.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/L7cIdc7.SrfqPgK 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` `5c97d3bd35b71a19104360930aa74b467c33a2b93c9d320325842c150e0b0c3b`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/L7cIdc7.SrfqPgK	1429504 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.81, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `a261214b5f4944e94265faf2bd20bef62b56986c6db1a4adcda4f6e7a816780f`	ole-package	OOXML xl/embeddings/L7cIdc7.SrfqPgK Ole10Native stream: OLE10nAtive	1416162 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.80, consistent with packed or encrypted content.

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