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

Static analysis result for SHA-256 5c9afd7fe9c499f1…

MALICIOUS

Office (OOXML) / .XLSX

622.2 KB Created: 2024-02-20 10:17:58 UTC Authoring application: Microsoft Excel 16.0300
MD5: 38cbbba46f4b3d6b6f4af18ca8c23cca SHA-1: 8da80af196f1d5ff3c9fe940c5c29a56e93b9b63 SHA-256: 5c9afd7fe9c499f102c27123afac513d83835023880208994cde562e9de88b30
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

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, suggesting it's being used to exploit a vulnerability for client execution. The anomaly in the Ole10Native stream size further supports this malicious intent.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/rYf5C.UW 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
bfe1486db85106d6958383687b6f56a65f095f5af1b16a22b51c72546e39f853		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/rYf5C.UW 939008 bytes
ooxml_oleobject_00_ole10native_00.bin
13233f7b086560dd930293f603078f4ecc55d667903e8039a7aff5a17afdefc8		 ole-package OOXML xl/embeddings/rYf5C.UW Ole10Native stream: oLE10nATivE 929024 bytes

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