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

Static analysis result for SHA-256 401f7664ecc21d41…

MALICIOUS

Office (OOXML) / .XLSX

756.6 KB Created: 2010-06-04 08:55:28 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-10-11
MD5: 534c913fe54a34e4e7e843fdb8c8943f SHA-1: 6899d08c3ee15bfbd9584d10be66ed120beaf2e9 SHA-256: 401f7664ecc21d411674cc96ccf6c6fe0795cccb33eebae6cdbab6bf9b6ba605
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model T1204.002 Malicious File

The file is an OOXML document containing an embedded OLE object, specifically identified as a Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the stream size. This strongly suggests the exploitation of a vulnerability within the Equation Editor component to embed and deliver a malicious payload. No scripts were extracted, and the document body appears to be a legitimate invoice, indicating the maliciousness is likely contained within the embedded object.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/nIEYpEb9.j6qj 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
fedbe6af6986f91d59e1a61372b6ffb389e30b4f08530cc086ea78be390050d5		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/nIEYpEb9.j6qj 1083904 bytes
ooxml_oleobject_00_ole10native_00.bin
a12a8ea7ad8f97bbd22683bd2885c6a6da78376971bb4a84cadab92411561e17		 ole-package OOXML xl/embeddings/nIEYpEb9.j6qj Ole10Native stream: oLE10nATiVE 1072999 bytes

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