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

Static analysis result for SHA-256 685cc3497ff584ff…

MALICIOUS

Office (OOXML) / .XLSX

650.5 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-10-24
MD5: 57fc45639ee9d13bc3ffecff9909b411 SHA-1: 3fc22067197b26464cbfbdeb2c93e7647f05b314 SHA-256: 685cc3497ff584ff81b43928940811e72836b67137bdc159be84703bbce05685
100 Risk Score

Malware Insights

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

The file is an OOXML document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this object carries a payload-like Ole10Native stream with an anomalous header, suggesting it's being used to exploit a vulnerability. This is a common technique for delivering second-stage malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/V6W.xvjS 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
8b4f5ab4a67c61b1a0d24e2a95e95b69b2adf4de9366a1e972f22f92afaed52e		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/V6W.xvjS 950272 bytes
ooxml_oleobject_00_ole10native_00.bin
777dde6a18c9fe92e97cf7980d05b3a9a9cc59b72cd581b4a20d04395bad455f		 ole-package OOXML xl/embeddings/V6W.xvjS Ole10Native stream: OlE10nAtiVe 940126 bytes

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