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

Static analysis result for SHA-256 ff6b339746f83950…

MALICIOUS

Office (OOXML) / .XLSX

609.1 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-08-05
MD5: 1e1bd82adf7514283984d7ef96755293 SHA-1: af365eea6d38acd78096c3d29fff495ea1f52654 SHA-256: ff6b339746f8395020052665f696b7f2762cf32b898acf4b342942a6f979aa52
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. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size, strongly suggesting exploitation of a known vulnerability (e.g., CVE-2017-11882) to execute arbitrary code. The embedded object's path and the stream name are logged as IOCs.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/4lqK.zNE6xsm 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
8299afe1db1466d8278f6900e4ec8e88edc8e5a542715932d49cac44612437f2		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/4lqK.zNE6xsm 901120 bytes
ooxml_oleobject_00_ole10native_00.bin
7a8c490aefaf1230bd306c33f80c4d828420884d23d7f8adfe832c254a97f5f3		 ole-package OOXML xl/embeddings/4lqK.zNE6xsm Ole10Native stream: Ole10natiVE 891467 bytes

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