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

Static analysis result for SHA-256 727ed08480bfdd32…

MALICIOUS

Office (OOXML) / .XLSX

704.8 KB Created: 2022-08-10 18:51:50 UTC Authoring application: Microsoft Excel 16.0300
MD5: 0454164895cd737982a3d625fb41085e SHA-1: fce6c3a361f9f6fe5050f1519eb249546bc25908 SHA-256: 727ed08480bfdd32124772ccccebb72c9815b86a8482ccebc1d0ff71330d56e0
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is an Excel spreadsheet containing an embedded OLE object, specifically identified as an Equation Editor. Heuristics indicate this object carries a payload-like stream with an anomalous header and a significantly larger declared inner size than the stream size, strongly suggesting it's a disguised executable or exploit. This points to an attack pattern involving spearphishing attachments designed to exploit vulnerabilities via embedded objects.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/Yedk.tWXx 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
9de577af9409eaf83622f80c187be1213f5a3a19118cffa746ac907e3e9ad6b4		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/Yedk.tWXx 967168 bytes
ooxml_oleobject_00_ole10native_00.bin
f1cafe0af33b567be5f4a42c330501df8f611c6d18c34659fbb9794457dbcf71		 ole-package OOXML xl/embeddings/Yedk.tWXx Ole10Native stream: Ole10NAtiVe 957016 bytes

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