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

Static analysis result for SHA-256 1d9b10edd74d4d97…

MALICIOUS

Office (OOXML) / .XLSX

654.0 KB Created: 2023-09-18 22:44:13 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-09-20
MD5: 86ec548550cced08a987c5c1abac565f SHA-1: 46f30c491125c67423cbe2c477c4f5814afbd220 SHA-256: 1d9b10edd74d4d9722aa2e5156abff9f6214ce391321ced3f644a8dd844e552e
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 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. This is a common delivery mechanism for malicious payloads.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/si9dn.Ws 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
67b8f3094ad6e6da5b714e62c803797bcc050b884f68eeaba21ca8aa6bee9c57		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/si9dn.Ws 893952 bytes
ooxml_oleobject_00_ole10native_00.bin
e2822837ccd0aba7da69c2d4d4b5d171134d804c4d2133995b862cba35f9f43e		 ole-package OOXML xl/embeddings/si9dn.Ws Ole10Native stream: OLE10NatiVe 884253 bytes

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