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

Static analysis result for SHA-256 939d2e9133c5f03a…

MALICIOUS

Office (OOXML) / .XLSX

688.6 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300
MD5: 38158d6200d58b91740a3e69940564c9 SHA-1: 6cdf9db7b6684216703bbbabd2a94d9179a60824 SHA-256: 939d2e9133c5f03ab4b822ee01cc93c37a8229031e786a387eea87d3cc2619e1
100 Risk Score

Malware Insights

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

The sample is an Office 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 delivery mechanism for malware, often initiated via spearphishing attachments.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin 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
1734f4d8d7da079b114355b81a4298abd6bece4fd92c1a4d657af845d6beb462		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 998400 bytes
ooxml_oleobject_00_ole10native_00.bin
a39b985c081a092e6d4f6af4fdab77a93060e7792c4e7933f5f0279c11da544f		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OlE10NatiVE 988052 bytes

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