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

Static analysis result for SHA-256 8c8949ea4366b524…

MALICIOUS

Office (OOXML) / .XLSX

628.3 KB Created: 2006-07-29 11:37:20 UTC Authoring application: Microsoft Excel 16.0300
MD5: e4e6fdd66c0b0083de2a3945c92b5c9a SHA-1: c5f24bd59ae8d6206919dc10101d8723b7944d1e SHA-256: 8c8949ea4366b524e7e6928c5a2a05a4738ecd0dde63af663fe95a4d18538b0f
100 Risk Score

Malware Insights

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

The XLSX file contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. This object exhibits an anomaly where it carries a payload-like Ole10Native stream, with a declared inner size significantly larger than the actual stream size. This strongly suggests the exploitation of a known vulnerability within the Equation Editor component to execute arbitrary code. The file is therefore likely used as a delivery mechanism for a secondary payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/8v94Hk.cYHj 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
22b2903b9b410d3265cb444897fa8c0bdd131f5c960d901ca313cfaf0efa0fd0		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/8v94Hk.cYHj 837120 bytes
ooxml_oleobject_00_ole10native_00.bin
663e41e60af0b65c63ade8120b41163a57138a79d11f2c990253acc8f6b6450b		 ole-package OOXML xl/embeddings/8v94Hk.cYHj Ole10Native stream: OLe10NatiVE 828350 bytes

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