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

Static analysis result for SHA-256 29cf482ebc92eebd…

MALICIOUS

Office (OOXML) / .XLSX

957.0 KB Created: 2020-06-30 06:04:05 UTC Authoring application: Microsoft Excel 15.0300
MD5: d8a36d9c0a60ab53566564f9eb8138bf SHA-1: ca19d3af4901369cdec39d3cb49d0dc4ad320fd6 SHA-256: 29cf482ebc92eebd275fb95e0a57b3929d5aebbff6aec8a5cff8fb6360e822fd
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1027 Obfuscated Files or Information

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. The embedded object's stream name and its anomalous characteristics are key indicators of this exploit.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/7rYf.dQfO 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
63695588100df74c6af7dc1d5cad0e9efa61bb5a5625eb470cecfd595a6ab331		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/7rYf.dQfO 1074688 bytes
ooxml_oleobject_00_ole10native_00.bin
96ec86bed5d9470d4657f8de8e6a3a31426033a35d3338da9213742d7fe8320d		 ole-package OOXML xl/embeddings/7rYf.dQfO Ole10Native stream: OlE10naTIVe 1063884 bytes

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