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

Static analysis result for SHA-256 bb04873f71f5135a…

MALICIOUS

Office (OOXML) / .XLSX

615.9 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-08-12
MD5: 35b9425ec2c8192b08bf3d72ff45ae20 SHA-1: 94c953149a8c8b520d073ac516efe223092ffd1e SHA-256: bb04873f71f5135a43c5abdcadf114c9258250b08fb75a83f6b431e40a5dc3cf
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 a significantly larger declared inner size than the actual stream size. This strongly suggests exploitation of a known vulnerability within the Equation Editor component to execute arbitrary code.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/0BVgahM.upu 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
994747ce0dd2b518941a43e02cf0d3e9321e646c2a727033f8b314209ff9d75d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/0BVgahM.upu 904704 bytes
ooxml_oleobject_00_ole10native_00.bin
d27931f2c5c7effc38f0af774c5cd95d6b2addb8573518f1d3b6095392993337		 ole-package OOXML xl/embeddings/0BVgahM.upu Ole10Native stream: OlE10naTive 895336 bytes

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