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

Static analysis result for SHA-256 c99437eec0210f43…

MALICIOUS

Office (OOXML) / .XLSX

12.0 KB Created: 2025-06-02 09:02:53 UTC Authoring application: Microsoft Excel 12.0000
MD5: 7d16aa9929d9b6275d3ab34b0a437a22 SHA-1: 1b73b1518f8419c611e275cb9adbd519e63a0769 SHA-256: c99437eec0210f43d875f30193d3ee448cab64b2fe184308ca5f050816b3fc96
120 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.002 Spearphishing Attachment T1059.005 Visual Basic

The sample is an Office document (XLSX) that contains an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object is anomalous and exploits CVE-2018-0798. The document body contains text designed to trick the user into enabling editing and macros, a common lure for malware delivery. No scripts were extracted, but the presence of the exploit and the lure strongly suggests the document is intended to download and execute a second-stage payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
929d561e8a46bdc83566d0362affdd4066ec6ff72f8df0760e46947a6b63edfb		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 4096 bytes
ooxml_oleobject_00_ole10native_00.bin
778fceb72c93b6296041391f446add870d4f4d5adcd7d3b0f4b2a7f6ab9e74f8		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: ole10naTIve 1631 bytes

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