Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 45be2740870ebe42…

MALICIOUS

Office (OOXML) / .XLSX

583.6 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-15
MD5: 83b0dfc062ae26043b4a1d77c5bb0ecf SHA-1: 33398ca86be5c6166af66442b92daa9f27b68ae3 SHA-256: 45be2740870ebe4272e62da02cbb6097ae4d4802000d50e514f3d5970b46eb50
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This technique is commonly used to download and execute a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/NCiymmySe.tML contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
15d2d4be6fdde018f1914d44eb9e4751ffe133bdd3afdb38d12ae60e3f45ad61		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/NCiymmySe.tML 797184 bytes
ooxml_oleobject_00_ole10native_00.bin
03f66a86c46107807ce7cfbd30f1b147488c8f2a20e6a647ecaf8653143559e7		 ole-package OOXML xl/embeddings/NCiymmySe.tML Ole10Native stream: olE10NaTIvE 788294 bytes

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