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

Static analysis result for SHA-256 c9d87f42852b7c18…

MALICIOUS

Office (OOXML) / .XLSX

686.1 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-09-07
MD5: 24394038cf7124deb092d49a060c707e SHA-1: 058d306b1c8f41bfbecbba39845d3cda6c546099 SHA-256: c9d87f42852b7c188b42b147e4422d158271ee647294112981a5fc9f6d848bda
100 Risk Score

Malware Insights

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

The file is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header, strongly suggesting exploitation of a known vulnerability (e.g., CVE-2017-11882) to execute arbitrary code. The embedded object and its anomalous stream are the primary indicators of malicious activity.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/hffbr.RMb0 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
4caffdb2bd29e5c7aaa8af0a4f99214e2d632c94fb61f83cd2bebce0c5bd1178		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/hffbr.RMb0 980992 bytes
ooxml_oleobject_00_ole10native_00.bin
1f3e452a2b372b920bdc92356b0f8f2090b2a7e1920de451cbc476ebbb63fdc8		 ole-package OOXML xl/embeddings/hffbr.RMb0 Ole10Native stream: OLe10NaTive 970857 bytes

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