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

Static analysis result for SHA-256 eef7c8aaab870856…

MALICIOUS

Office (OOXML) / .XLSX

733.4 KB Created: 2023-09-06 22:27:29 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-09-07
MD5: 0c132892597855f142bba5f5812d9afe SHA-1: 7b84eaf37baf98ce5e3839da50e6e6016c8c90af SHA-256: eef7c8aaab8708563b10a4cfb74ff6856deaaa7ff0db4d4bd7cb709fd8103b1f
100 Risk Score

Malware Insights

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

The file contains an embedded OLE object, specifically identified as a Equation Editor object with an anomalous Ole10Native stream. This strongly suggests exploitation of a known Equation Editor vulnerability (e.g., CVE-2017-11882) to execute arbitrary code. The anomalous stream size and entropy indicate it likely contains a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/C0.9d 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
5a84f5b135de12b7b6f64aa5d1128fdc1598b005ebf8194a2e98a43a5b9fe3b1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/C0.9d 1070592 bytes
ooxml_oleobject_00_ole10native_00.bin
139d37632eca83a42cfb3ca6e7f9f74dc1574a457c6fa7ef9b7740cdcd4da63d		 ole-package OOXML xl/embeddings/C0.9d Ole10Native stream: OLE10nATIvE 1059505 bytes

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