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

Static analysis result for SHA-256 4843f7c8ac3d9537…

MALICIOUS

Office (OOXML) / .XLSX

735.3 KB Created: 2023-09-06 21:49:39 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-09-07
MD5: c6a856b381728a69465a7f3d46bc3859 SHA-1: 3f757a98f147fe16d9c8413c1272570445707b47 SHA-256: 4843f7c8ac3d9537258ed64787adf17a528caa58e5a4c3a457d79445cd9b5ea8
100 Risk Score

Malware Insights

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

The file is an Excel document containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. This object carries a payload-like Ole10Native stream with an anomalous header, indicating it's likely used to exploit a known vulnerability for delivering a secondary payload. The presence of an embedded OLE object and the specific Equation Editor exploit points towards a common delivery mechanism for malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/6YZKmmP.NbNaZGs 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
8ecfd929fdaf82aecd8feee05ba0aef245536b782ae596a0f161be0c0e7dbf79		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/6YZKmmP.NbNaZGs 1091584 bytes
ooxml_oleobject_00_ole10native_00.bin
f443b4fac7197407837c31606e8be4d84926b8a0d1f21ef236332419410b86ff		 ole-package OOXML xl/embeddings/6YZKmmP.NbNaZGs Ole10Native stream: OLe10nATIvE 1080829 bytes

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