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

Static analysis result for SHA-256 50e6ab9438865ecb…

MALICIOUS

Office (OOXML) / .XLSX

605.4 KB Created: 2021-02-03 07:57:22 UTC Authoring application: Microsoft Excel 15.0300
MD5: e089656370c797425da893e6c9665452 SHA-1: 0ac2c75ffea9b476d6981c6ab3fafcaea65a5112 SHA-256: 50e6ab9438865ecb8b098bccea06958ef498d469c9c16609ab1c65017f991e99
140 Risk Score

Malware Insights

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

The sample is an Excel file containing an embedded Equation Editor OLE object. Heuristics indicate this object is anomalous and carries a payload, specifically triggering CVE-2018-0798. This suggests the file is designed to exploit this vulnerability for initial execution, likely delivered as a spearphishing attachment.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/EJ7D.V9gbS 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
d32cd522594de6c771fa5e9ddec16b15f4ac4ae611a1c63e6ba55815666e72d3		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/EJ7D.V9gbS 815616 bytes
ooxml_oleobject_00_ole10native_00.bin
abdc512d24eb9670ab247935cce5557b8c743898493053c36bdef9c31ca5266d		 ole-package OOXML xl/embeddings/EJ7D.V9gbS Ole10Native stream: Ole10NATIvE 806716 bytes

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