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

Static analysis result for SHA-256 7a6367cdd9d6d0db…

MALICIOUS

Office (OOXML) / .XLSX

654.6 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-09-26
MD5: bb1be8aabfa3b7b55acaf121f7be3a05 SHA-1: a5a02621318a15252808779c217e49e876174ed9 SHA-256: 7a6367cdd9d6d0db0c685487937d09f9881cbbcdc936b3750bd89ed7fcbad407
100 Risk Score

Malware Insights

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

The file is an Office document 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 and a significantly larger declared inner size than the actual stream size. This strongly suggests exploitation of a vulnerability within the Equation Editor component to execute arbitrary code.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/vKlT.JyZ 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
dc10fdb015c4bb1902a59e679bbe0e0a2396b7d29f0db708881ed4fdffcfee9b		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/vKlT.JyZ 921088 bytes
ooxml_oleobject_00_ole10native_00.bin
87a87cae7cff1a7ce5dccb7da6498cc8eab6dd06dcf9849b04d2c613dc64a55d		 ole-package OOXML xl/embeddings/vKlT.JyZ Ole10Native stream: oLE10NatiVe 910871 bytes

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