References and Resources vsFTPd 2.3.4 Backdoor (CVE-2011-2523) CVE Details Exploit Database Entry Samba RCE (CVE-2007-2447) Samba Security Advisory CVE Details UnrealIRCd Backdoor (CVE-2010-2075) Official Advisory Exploit Database Entry General Resources Metasploitable 2 Documentation Nmap Documentation