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

Static analysis result for SHA-256 987eb254efd0f44e…

MALICIOUS

Office (OOXML) / .XLSX

720.3 KB Created: 2019-02-26 14:42:35 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-08-09
MD5: c12feb775419866916cad4b2dcc1328b SHA-1: f9cf4ac01f46fbdbe6fee6c2f5c93ad95ec09ee4 SHA-256: 987eb254efd0f44e974cf17a3815abff007795bd5b2a34f31450364e3f49d9a0
108 Risk Score

Malware Insights

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

The sample is an Excel spreadsheet containing an embedded OLE object, specifically an Equation Editor object. This object carries a payload-like Ole10Native stream with an anomalous header, indicating it's likely designed to execute malicious code. The document body contains text resembling invoice or payment details, supporting the lure mechanism.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/FVLhrxO.A9kx 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
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
77af812e227f31bb4ec3379da2568a2ce3cc0c5e8ded35f8c2c29d0564fc20c9		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/FVLhrxO.A9kx 973824 bytes
ooxml_oleobject_00_ole10native_00.bin
621f3f172d3b4ad9fd8a6fff1d635c261f585febbb0d185ed0f742fc35e439ea		 ole-package OOXML xl/embeddings/FVLhrxO.A9kx Ole10Native stream: oLE10naTiVE 963857 bytes

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