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

Static analysis result for SHA-256 48d6ef90026a8919…

MALICIOUS

Office (OOXML) / .XLSX

719.7 KB Created: 2023-09-19 06:25:18 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-10-02
MD5: 5b2e1828e0290998f9db8b52f164f2d7 SHA-1: 71b98b3fcba408478bfa611be6985b9c03437413 SHA-256: 48d6ef90026a89196ed71552013431907514515ff28cd42fca4cf842e3f2da72
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 Malicious Link

The sample is an Office 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 (e.g., CVE-2017-11882). This technique is commonly used to deliver a second-stage malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/CkU1.cm 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
1435f58ef979c926acba0463fdab0dc9a22273410e6def9f67498bf3ac08aafa		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/CkU1.cm 1067520 bytes
ooxml_oleobject_00_ole10native_00.bin
9098a48614892faadfdd78d2b5493339e8227c6a6fb01fc8768ed2bf9d98b060		 ole-package OOXML xl/embeddings/CkU1.cm Ole10Native stream: OlE10NaTivE 1056367 bytes

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