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

Static analysis result for SHA-256 e01c99c34b581a13…

MALICIOUS

Office (OOXML) / .XLSX

615.0 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-10-06
MD5: 50a1039bea7bf6220fd06559c0a5be20 SHA-1: 91c6d52784cf54457cc5cdb67ef2d3f404100786 SHA-256: e01c99c34b581a13f712ab7f5c5d01dd34a06c74fb05bc638aee86552173c787
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1204.002 User Execution: Malicious File

The file is an OOXML 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 size discrepancy, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This technique is commonly used to deliver a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/muRF3g.hyJlC1s 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
a4ee4d6280ec6af1b6b1eba0e55d30f37ede702f681243c9fbe4d785713d866b		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/muRF3g.hyJlC1s 925696 bytes
ooxml_oleobject_00_ole10native_00.bin
14d5163f180673bc1862023c973bc14b98c57cb0dd9ed157a94f19ce02064fc0		 ole-package OOXML xl/embeddings/muRF3g.hyJlC1s Ole10Native stream: OlE10nAtIVe 915823 bytes

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