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

Static analysis result for SHA-256 4c0e09c365aed98c…

MALICIOUS

Office (OOXML) / .XLSX

620.1 KB Created: 2023-09-12 23:10:22 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-09-13
MD5: 21c495c735627bf63e7d9120303f6c72 SHA-1: 4c06c8c532c9737249ac87d9d4ee461c18cbc7fb SHA-256: 4c0e09c365aed98cfef29811c4493f0a99706c350d3bd86e3d5af8d1618f14c2
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 Malicious Link

The XLSX file contains an embedded OLE object, specifically identified as a Equation Editor object. This object exhibits an anomaly where the Ole10Native stream appears to carry a payload, indicated by an unusually large declared inner size compared to the stream size. This strongly suggests the exploitation of a known vulnerability within the Equation Editor component to deliver a malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/uRf.7PI 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
345d3e63082f869b8b30d90ca967981705fe3770d76bb5d2d351ad3edfe67468		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/uRf.7PI 926208 bytes
ooxml_oleobject_00_ole10native_00.bin
ca4ba872bfd2cbdf7baf6198aa47a63e1e1574036f5382ae653f3f39eddb75c8		 ole-package OOXML xl/embeddings/uRf.7PI Ole10Native stream: ole10natIvE 916413 bytes

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