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

Static analysis result for SHA-256 6a612c364e02c35b…

MALICIOUS

Office (OOXML) / .XLSX

741.2 KB Created: 2021-08-09 02:12:21 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-02-23
MD5: 3442bc360be6b75a8524fbc60c0f6fb7 SHA-1: 907df1e927821ed889a04bd33f8373b2e251a2f3 SHA-256: 6a612c364e02c35bcf1ebd4c04d6b4f5a9d39bc6a52fe40ae423fdcac667646b
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an Excel file containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. Heuristics indicate exploitation of CVE-2018-0798 via an anomalous Equation Editor native stream, which carries a payload-like Ole10Native stream. This suggests the file is designed to execute arbitrary code through the Equation Editor vulnerability.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/nlZB.aSf1di contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • 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
7e6c45b4b5fbd5d43e5a87475788f056b418944dcd615a5e36cffa4a8210266c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/nlZB.aSf1di 1053184 bytes
ooxml_oleobject_00_ole10native_00.bin
fb28607d6f14c66d57a48658468be8991493a10413e72ac6eb8b71e261e7b136		 ole-package OOXML xl/embeddings/nlZB.aSf1di Ole10Native stream: ole10nATIVe 1042349 bytes

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