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

Static analysis result for SHA-256 a3119ebe8ad88443…

MALICIOUS

Office (OOXML) / .XLSX

595.9 KB Created: 2023-08-29 23:34:18 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-08-30
MD5: d601bb9786ae2d84aeb90833eb145131 SHA-1: c2c725424d253bec11012ebe33deff6870a44845 SHA-256: a3119ebe8ad88443c6f11ed30c1159d16d30ffa6e3ba24d1072102c47d2ffc84
100 Risk Score

Malware Insights

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

The file is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header, suggesting it's being used to exploit a vulnerability. This is a common technique for delivering second-stage malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/cBRg5u.GJXT 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
df3cfb8b8b733fd68bcf09809dac6538c8bd7cb71684f28b13dcda383b86fcef		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/cBRg5u.GJXT 864768 bytes
ooxml_oleobject_00_ole10native_00.bin
ba984ed8df7211a7c7edd778f1c7b8daf01e6d16d782e9a138e3a7d01c11df5f		 ole-package OOXML xl/embeddings/cBRg5u.GJXT Ole10Native stream: Ole10naTiVE 855062 bytes

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