Provide references for CVE-2011-2523.
Where can I find more information about CVE-2011-2523?
References are available at: https://security-tracker.debian.org/tracker/CVE-2011-2523, https://access.redhat.com/security/cve/cve-2011-2523, https://www.openwall.com/lists/oss-security/2011/07/11/5, https://vigilance.fr/vulnerability/vsftpd-backdoor-in-version-2-3-4-10805, https://packetstormsecurity.com/files/102745/VSFTPD-2.3.4-Backdoor-Command-Execution.html, http://packetstormsecurity.com/files/162145/vsftpd-2.3.4-Backdoor-Command-Execution.html.