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

Static analysis result for SHA-256 424fff8525a1a9f4…

MALICIOUS

Office (OOXML) / .XLSX

770.6 KB Created: 2021-12-06 14:45:17 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-03-22
MD5: d1c7c5a0f685d94388301db44319a327 SHA-1: 4ea61fba63e9a07a71e18cd0b6cb3daf898fc19c SHA-256: 424fff8525a1a9f460e50a5041495045011536cac1b8977fc170d1d373a7cfa2
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The sample is an OOXML file 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 size difference, strongly suggesting it's being used to exploit a known vulnerability. This technique is commonly used to deliver second-stage malware. The specific embedded object path and stream name are provided as IOCs.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/SsJ6stmW.0Y 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
6c9bcffbbd3bd40319ecd8706c59de65fcb3bd29f50c6d30c6e9b983868c1efb		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/SsJ6stmW.0Y 1047552 bytes
ooxml_oleobject_00_ole10native_00.bin
e8f46e630e08715aab21924c07c7f8b9078e3c3c0cadc803c21b44dd96718f3a		 ole-package OOXML xl/embeddings/SsJ6stmW.0Y Ole10Native stream: OlE10NatiVe 1036917 bytes

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