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

Static analysis result for SHA-256 23f794691579a0dd…

MALICIOUS

Office (OOXML) / .XLSX

688.7 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-30
MD5: c9a266dd92e7214811e784d8c830deaf SHA-1: 766f7cec41dd4c1be6ecedf18f5f95ed656d962a SHA-256: 23f794691579a0ddc1a32e91d9de913fe4ac8b3dbc8d65f3cf3c83522fbd171f
100 Risk Score

Malware Insights

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

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 Equation Editor object carries a payload-like Ole10Native stream with an anomalous header, suggesting it's designed to exploit a vulnerability. This is a common delivery mechanism for malware, often initiated via spearphishing attachments.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/FPmlPro.wyWjRT 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
8944ec87126417e8c1f2a0ae6124a3edd5b59944f7d227bc3f9d63c18400143d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/FPmlPro.wyWjRT 933888 bytes
ooxml_oleobject_00_ole10native_00.bin
50d8096330497e3361ee4bf037ebf95fd90dd9c3220f7e568e6527c7aad6d61d		 ole-package OOXML xl/embeddings/FPmlPro.wyWjRT Ole10Native stream: OLE10NaTivE 923770 bytes

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