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

Static analysis result for SHA-256 26fdef36132e8b25…

MALICIOUS

Office (OOXML) / .XLSX

740.8 KB Created: 2023-08-28 00:12:05 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-08-28
MD5: 1f0fdb69e5821d12bde66b5d9d12d0f9 SHA-1: bc2fcd2a9e4ab68925c5574946e6d13f236d1c26 SHA-256: 26fdef36132e8b25558afa59b468bc3d3b33738c87a5768f61e115bc7b84380b
100 Risk Score

Malware Insights

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

The XLSX file contains 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 it's used to exploit a vulnerability. This technique is commonly used to deliver second-stage malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/f5.dv 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
5aba952b3cf9ec9cc3d12b0a6bfb21df1cd108668e6b8f10952bb108fb765478		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/f5.dv 1035264 bytes
ooxml_oleobject_00_ole10native_00.bin
49e2c014274085c27ae06db61664e6b303dd8caf7b99386b4e307e96a1a4f44d		 ole-package OOXML xl/embeddings/f5.dv Ole10Native stream: Ole10NATIVe 1024928 bytes

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