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

Static analysis result for SHA-256 5de125a586b47d88…

MALICIOUS

Office (OOXML) / .XLSX

742.7 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-15
MD5: a5317ee4fef52c694a22481bb41d1ae6 SHA-1: 19e6424882336c6d1e224633e2859e47687c5067 SHA-256: 5de125a586b47d88802f23afe26ec83b71fdd54689f17fd27573a737b0b81dae
100 Risk Score

Malware Insights

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

The sample is an Office document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size and header, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This technique is commonly used to deliver a second-stage malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/nXRK3.VehXli 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
69992d22e36602fbd01e698501cc3d358bcee9deb33f0e2e480c02430b62ebb2		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/nXRK3.VehXli 1075712 bytes
ooxml_oleobject_00_ole10native_00.bin
7a14410f5c219dc6e844c6b07b103dc90ae6b6ff1dbdf6dd87a8ef06687bd9a1		 ole-package OOXML xl/embeddings/nXRK3.VehXli Ole10Native stream: Ole10nativE 1064766 bytes

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