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

Static analysis result for SHA-256 04b9492b88f700af…

MALICIOUS

Office (OOXML) / .XLSX

588.8 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-09-06
MD5: 9e5c48a7fd575de8b43ba2cabac51c29 SHA-1: bad777482be62425bb3b1ed3c0dd74d4dd9b09ea SHA-256: 04b9492b88f700af2e6e0baf2e0e2aca7e40ca1f0908553a28747fbda345b4a2
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File T1027 Obfuscated Files or Information

The XLSX file contains 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 and an unexpectedly large declared inner size, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This indicates the file is designed to exploit this vulnerability to execute a secondary payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/pFSygfWv.R27vN 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
1dec20be510953b534341f1d955a082c4bf66350f9a0918b10e1d704fa9621b8		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/pFSygfWv.R27vN 814592 bytes
ooxml_oleobject_00_ole10native_00.bin
b325fe694c2ba257689ade296c98513d89d210d7a2ffecc65bba562b77cb2d9f		 ole-package OOXML xl/embeddings/pFSygfWv.R27vN Ole10Native stream: olE10NAtIve 805578 bytes

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