Man-in-the-Middle (MitM) attack in Postfix - CVE-2011-0411
Published: March 17, 2011 / Updated: June 8, 2025
Vulnerability identifier: #VU32859
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2011-0411
CWE-ID: CWE-300
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform MitM attack.
The vulnerability exists due to incorrect implementation of STARTTLS command that does not properly restrict I/O buffering, which allows man-in-the-middle
attackers to insert commands into encrypted SMTP sessions by sending a
cleartext command that is processed after TLS is in place, related to a
"plaintext command injection" attack.
Affected software
Postfix
Gentoo Linux
Fedora
postfix (Alpine package)
pure-ftpd
Gentoo Linux
Fedora
postfix (Alpine package)
pure-ftpd
How to mitigate CVE-2011-0411
Install update from vendor's website.
Postfix - update to 2.4.16
postfix (Alpine package) - update to 2.6.9-r0
pure-ftpd - update to 1.0.30-1.el6
postfix (Alpine package) - update to 2.6.9-r0
pure-ftpd - update to 1.0.30-1.el6
External References
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705
- http://lists.apple.com/archives/Security-announce/2011//Oct/msg00003.html
- http://lists.fedoraproject.org/pipermail/package-announce/2011-March/056559.html
- http://lists.fedoraproject.org/pipermail/package-announce/2011-March/056560.html
- http://lists.opensuse.org/opensuse-security-announce/2011-05/msg00005.html
- http://secunia.com/advisories/43646
- http://secunia.com/advisories/43874
- http://security.gentoo.org/glsa/glsa-201206-33.xml
- http://securitytracker.com/id?1025179
- http://support.apple.com/kb/HT5002
- http://www.debian.org/security/2011/dsa-2233
- http://www.kb.cert.org/vuls/id/555316
- http://www.kb.cert.org/vuls/id/MORO-8ELH6Z
- http://www.oracle.com/technetwork/topics/security/cpuapr2011-301950.html
- http://www.osvdb.org/71021
- http://www.postfix.org/CVE-2011-0411.html
- http://www.redhat.com/support/errata/RHSA-2011-0422.html
- http://www.redhat.com/support/errata/RHSA-2011-0423.html
- http://www.securityfocus.com/bid/46767
- http://www.vupen.com/english/advisories/2011/0611
- http://www.vupen.com/english/advisories/2011/0752
- http://www.vupen.com/english/advisories/2011/0891
- https://exchange.xforce.ibmcloud.com/vulnerabilities/65932