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

Static analysis result for SHA-256 33c12f45714597f7…

MALICIOUS

Office (OOXML) / .XLSX

190.3 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: 468c8b371605ce61c72bea20d6ae68c9 SHA-1: dc0dcaba465d5aae593586279d99129082c013db SHA-256: 33c12f45714597f74849e4ea5932eaf8b4c1bc90cebc945ca73e384d379371ab
168 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1059 Command and Scripting Interpreter

The critical ClamAV detection and high-severity heuristics for Equation Editor OLE objects and CVE-2018-0798 indicate the file is a downloader. The embedded OLE object likely exploits a vulnerability to fetch and execute a secondary payload, consistent with the Formbook family's known behavior. No document body or scripts were extracted, limiting further analysis of the specific lure.

Heuristics 5

  • 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.
  • ClamAV: Doc.Downloader.Formbook-bc97c1e0c33c3c93-9951465-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Formbook-bc97c1e0c33c3c93-9951465-0
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
d8fadf8774b5b190e3063b4c8e22b48d70a75d65da23712f10ac306d7468440f		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 4608 bytes
ooxml_oleobject_00_ole10native_00.bin
80ff9652c5128c31ff698121a63e367017b81aefdf2925a21b13685020989041		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OLe10nAtIVE 2012 bytes
emf_00.emf
5294347291c5b056a3d08e26fb03e2117056cf5145e25e6f0cc2ae5b4c8b74a5		 ooxml-emf OOXML EMF part: xl/media/image2.emf 1099960 bytes

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