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Author: javascript-2020

blog/25-12-04/bypass-csp/proxy/mitm-proxy.js

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+        
+        
+        
+        
+        var net   = require('net');
+        var tls   = require('tls');
+        var fs    = require('fs');
+        
+        var cert            = fs.readFileSync('cert.pem');
+        var key             = fs.readFileSync('key.pem');
+        var secureContext   = tls.createSecureContext({cert,key});
+        
+        var domains   = ['example.com','main.com'];
+        var host      = '127.0.0.1';
+        var port      = 1080;
+        var server    = net.createServer(connection).listen(port,host);
+        console.log(`HTTP CONNECT MITM proxy listening on ${host}:${port}`);
+
+        
+        function connection(client){
+                                                                                console.log('client connect');          
+              client.once('data',data=>{
+                
+                    var req       = data.toString().split('\r\n');
+                    var connect   = req[0];
+                                                                                //  https only                    
+                    if(connect.indexOf('CONNECT')==-1){
+                          client.end('HTTP/1.1 400 Bad Request\r\n\r\n');
+                          return;
+                    }
+                    
+                    var parts   = connect.split(' ');
+                    var url     = parts[1];
+                    var host    = url.split(':')[0];
+                    var port    = url.split(':')[1];
+                                                                                console.log('client',host,port);
+                    client.write('HTTP/1.1 200 Connection Established\r\n\r\n');
+        
+                    if(domains.includes(host)){
+                          proxy(client,host,port);
+                          return;
+                    }
+                    
+                    var upstream    = net.connect(port,host);
+                    upstream.on('error',()=>client.destroy());
+                    
+                    client.pipe(upstream);
+                    upstream.pipe(client);
+                    
+              });
+              
+        }//connection
+
+
+        function proxy(client,host,port){
+                                                                                console.log('proxy');
+              var clientTls   = new tls.TLSSocket(client,{isServer:true,secureContext,ALPNProtocols:['http/1.1']});
+              clientTls.on('error',err=>{console.error(err);client.destroy(err)});
+              
+              var upstream    = tls.connect({host,port,servername:host,ALPNProtocols:['http/1.1'],rejectUnauthorized:false});
+              upstream.on('error',err=>clientTls.destroy(err));
+        
+              upstream.once('secureConnect',()=>{
+                                                                                console.log('secureConnect');        
+                    proxy.client(clientTls,upstream);
+                    proxy.upstream(clientTls,upstream);
+                    
+              });
+              
+        }//proxy
+
+        var hdr   = {};
+        hdr.rem   = (hdrs,name)=>hdrs.replace(new RegExp(`${name}.*\r\n`,'i'),'');
+        hdr.add   = (hdrs,hdr)=>hdrs.slice(0,-2)+hdr+'\r\n'+hdrs.slice(-2);
+        
+        proxy.client    = function(clientTls,upstream){
+          
+              var buf     = ''
+              var done    = false;
+  
+              clientTls.on('data',chunk=>{
+                
+                    if(done){
+                          upstream.write(chunk);
+                          return;
+                    }
+                    
+                    buf      += chunk
+                    var end   = buf.indexOf('\r\n\r\n');
+                    if(end!==-1){
+                          done        = true;
+                          var hdrs    = buf.slice(0,end+4);
+                          var rest    = buf.slice(end+4);
+                                                                                // Rewrite header
+                          //headers = headers.replace(/User-Agent:.*\r\n/i,'User-Agent: MITM-Proxy\r\n');
+  
+                          upstream.write(hdrs);
+                          if(rest){
+                                upstream.write(rest);
+                          }
+  
+                          clientTls.pipe(upstream);
+                    }
+                    
+              });
+        
+        }//client
+        
+
+        proxy.upstream    = function(clientTls,upstream){
+          
+              var buf     = ''
+              var done    = false;
+  
+              upstream.on('data',chunk=>{
+                
+                    if(done){
+                          clientTls.write(chunk);
+                          return;
+                    }
+                    
+                    buf      += chunk
+                    var end   = buf.indexOf('\r\n\r\n');
+                    if(end!==-1){
+                          done        = true;
+                          var hdrs    = buf.slice(0,end+4);
+                          var rest    = buf.slice(end+4);
+                                                                                console.log('\n\n','['+hdrs+']','\n\n');
+//                          hdrs    = hdr.rem(hdrs,'content-security-policy');
+                          hdrs    = hdr.add(hdrs,'x-proxy: test');
+                                                                                console.log('\n\n','['+hdrs+']','\n\n');
+                          clientTls.write(hdrs);
+                          if(rest){
+                                clientTls.write(rest);
+                          }
+  
+                          upstream.pipe(clientTls);
+                          
+                    }
+              });
+        
+        }//remote
+        
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