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

Static analysis result for SHA-256 391bf249606d77b0…

MALICIOUS

Office (OOXML) / .XLSX

702.0 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-20
MD5: 4b6a55859d05b0e97ebcaf9f14b7cb1b SHA-1: 29a547194e1ac0fc06178c4bfb51f65ed1c7369e SHA-256: 391bf249606d77b0c2998770b01112c6f9caa1c1627c6bd65fd948550781e1cc
100 Risk Score

Malware Insights

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

The XLSX file contains an embedded OLE object, specifically identified as an Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header, suggesting it's designed to exploit a vulnerability. This points to a likely attack pattern involving the exploitation of the Equation Editor component to execute a malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/CB.MuV9Nu 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
a452ecb366a0e9ea74ddb73fe0a0acdf363d06e6fcc84c8bbea3ae4f93723ee1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/CB.MuV9Nu 1035264 bytes
ooxml_oleobject_00_ole10native_00.bin
1f3c1489ef29f56bb8eee36833e9ceae47e62ed45b2df4cb4ac8ba3c668b482e		 ole-package OOXML xl/embeddings/CB.MuV9Nu Ole10Native stream: OLE10natIVE 1024650 bytes

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