https://www.warkruid.com/tags/openssl/Recent content in openssl on Warkruid's WeedsHugo -- gohugo.ioenFri, 08 Apr 2022 09:18:12 +0200https://www.warkruid.com/openssl-living-of-the-land/Fri, 08 Apr 2022 09:18:12 +0200https://www.warkruid.com/openssl-living-of-the-land/There was a question on stackoverflow about the OpenSSL s_client functionality in relation to SMTP mail. This question seemed a “red team” question to me. (Red Team stands for a team that attacks a site or service to test it’s security) How can you use OpenSSL to send mail out of a system? Let’s take a look. You can pipe SMTP commands into openssl with “«<” SMTPSERVER="smtp.example.com" SMTPPORT=587 SMTPCOMMANDS="QUIT" openssl s_client -crlf -quiet -starttls smtp -connect ${SMTPSERVER}:${SMTPPORT} <<< ${SMTPCOMMAND} Openssl connects to the smtp server via ttls and opens a command line shell.