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

Static analysis result for SHA-256 23d87b6268b3aa84…

MALICIOUS

Office (OOXML) / .XLSX

634.4 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-09
MD5: 994cf300e9078c09abdd7d95df6eadb4 SHA-1: e3adfa06cb686203fd689c518b3544b62ac9ab52 SHA-256: 23d87b6268b3aa8446d0101b1268b1805f0427ad176d82245e873955337f7ac2
100 Risk Score

Malware Insights

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

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 impossible header and a significant discrepancy between declared and actual stream sizes. This strongly suggests the exploitation of a vulnerability within the Equation Editor component to facilitate the delivery of a secondary malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/U46rVb.cDde0 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
81163131a2ec3fafb14d43e570ba4e31fef55653b4082b00aaf214c90ecc0f7b		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/U46rVb.cDde0 890368 bytes
ooxml_oleobject_00_ole10native_00.bin
06a176544c03670d0cfe7c3dbe7a09c92fbf31603c8d3e9a64e202b0a2c6ae11		 ole-package OOXML xl/embeddings/U46rVb.cDde0 Ole10Native stream: oLE10NAtivE 881111 bytes

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