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Hi you guys,<br><br>I proposed stunnel as a potential solution to our product about 4-5 months ago and I am in the process of testing a prototype I have built around that proposition. <br>I am using stunnel v. 4.41. I am relatively new to stunnel myself.<br><br>The env. is as follows:<br>We are trying to secure an rdp connection from a java applet running in a web browser into a windows 2008 server machine behind our firewall.<br>Presently, the java applet opens up an RDP connection into a machine (I will call it the SSL machine) where Stunnel is presently installed.<br>Stunnel then forwards properly the incoming traffic (from portA) into its final destination (i.e: the windows Server 2008 machine) on port B.<br>Further, I have configured Stunnel to use an SSL certificate. (Although, I have not been able to test that yet to make sure it works)<br><br>Anyhow, it is all working as expected and I am pretty happy about the proof of concept. <br>However, while testing it a bit, I noticed that it was relatively easy to bring stunnel down. The way I went about it, was to simply run a "telnet IP_of_MySSLMachine portA" from any DOS command window from any machine with internet access. From the Stunnel logs, I can tell that I get a response from Stunnel and on the DOS window side, I have a cursor waiting for input....<br>Writing any gibberish into that DOS windows and waiting a little bit makes stunnel stop and die in the SSL machine. I found nothing in the stunnel log, but grepping in the /var/log/, I found the segfault<br><br>sslmahine:/var/log/# grep stunnel messages<br>kernel: [1996904.624042] stunnel [19696]: segfault at 8 ip b768d361 sp b7601210 error 4 in <br>libc-2.7.so[b7621000+138000]<br><br>After another telnet execution, few days later:<br>sslmahine:/var/log/# grep stunnel messages<br>kernel: [4930384.164316] stunnel [14540]: segfault at 8 ip b7629b61 error 6 in <br>libc-2.7.so[b75bd000+138000]<br><br>Basically, if I don't issue that telnet command, stunnel works properly. As soon as I issue that command and start typing few things in that DOS console, stunnel dies. I have to manually restart it.<br><br><b>Question:</b><br>I was wondering if you guys could shed some light into this behavior. Is it a known behavior/bug? Is there a way to solve it by maybe upgrading into a later version of stunnel?<br>Also, I was thinking to block telnet altogether at the firewall level, but then I am not sure what other protocols could people use to hack into the system...so should I block all of them? <br>And, finally is there a more secure way to setup stunnel?<br><br>Thank you in advance<br>
Mehdi/ </div></body>
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