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

Static analysis result for SHA-256 9b8785cfbc8fc576…

MALICIOUS

Office (OOXML) / .XLSX

698.1 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-07-27
MD5: 2639dee773ed34e8ce6be414ec4c7060 SHA-1: 1c1bde3e5586406bdbb4cecc9cf9a4a5a202bc66 SHA-256: 9b8785cfbc8fc5765b5fb868e60433352bbadb455e36f4258c7931624196a72a
100 Risk Score

Malware Insights

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

The sample is an Excel file containing an embedded OLE object, specifically identified as a Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the actual stream size. This strongly suggests exploitation of a known Equation Editor vulnerability (e.g., CVE-2017-11882) to execute arbitrary code, likely leading to the download and execution of a secondary malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/V7IYeEZ.PI 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
e2f6f38763cc1208da592e556cd6473e6823bf5352246dde49bdfa3cd5601ed6		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/V7IYeEZ.PI 1013248 bytes
ooxml_oleobject_00_ole10native_00.bin
1ada74b5f047fe06da06a7d29960beea78356a8b14fec95ea832417ad875a0e1		 ole-package OOXML xl/embeddings/V7IYeEZ.PI Ole10Native stream: OLe10NATIve 1002533 bytes

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