详细描述
telnet后台程序telnetd实现服务器端的TELNET虚拟终端协议。
telnetd的实现上存在缓冲区溢出漏洞，远程攻击者可能利用此漏洞控制服务器。
TELNET协议具有数据流的加密机制，当通过TELNET协议提供加密密钥时，其长度在被复制到固定大小缓冲区之前没有得到验证，漏洞相关代码位于函数"encrypt_keyid()" (crypto/heimdal/appl/telnet/libtelnet/encrypt.c and contrib/telnet/libtelnet/encrypt.c)
解决办法
厂商补丁：
FreeBSD
-------
目前厂商已经发布了升级补丁以修复这个安全问题，请到厂商的主页下载：
http://www.freebsd.org/security/index.html
REDHAT
Name: RHSA-2011:1854
Hyperlink:http://rhn.redhat.com/errata/RHSA-2011-1854.html
External Source: REDHAT
Name: RHSA-2011:1853
Hyperlink:http://rhn.redhat.com/errata/RHSA-2011-1853.html
External Source: REDHAT
Name: RHSA-2011:1852
Hyperlink:http://rhn.redhat.com/errata/RHSA-2011-1852.html
External Source: REDHAT
Name: RHSA-2011:1851
Hyperlink:http://rhn.redhat.com/errata/RHSA-2011-1851.html
DEBIAN
External Source: DEBIAN
Name: DSA-2375
Hyperlink:http://www.debian.org/security/2011/dsa-2375
External Source: DEBIAN
Name: DSA-2373
Hyperlink:http://www.debian.org/security/2011/dsa-2373
External Source: DEBIAN
Name: DSA-2372
Hyperlink:http://www.debian.org/security/2011/dsa-2372
SUSE:
External Source: SUSE
Name: SUSE-SU-2012:0056
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00015.html
External Source: SUSE
Name: openSUSE-SU-2012:0051
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00014.html
External Source: SUSE
Name: SUSE-SU-2012:0050
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00011.html
External Source: SUSE
Name: SUSE-SU-2012:0042
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00010.html
External Source: SUSE
Name: SUSE-SU-2012:0024
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00007.html
External Source: SUSE
Name: openSUSE-SU-2012:0019
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00005.html
External Source: SUSE
Name: SUSE-SU-2012:0018
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00004.html
External Source: SUSE
Name: SUSE-SU-2012:0010
Hyperlink:http://lists.opensuse.org/opensuse-security-announce/2012-01/msg00002.html
FEDORA:
External Source: FEDORA
Name: FEDORA-2011-17493
Hyperlink:http://lists.fedoraproject.org/pipermail/package-announce/2012-January/071640.html
External Source: FEDORA
Name: FEDORA-2011-17492
Hyperlink:http://lists.fedoraproject.org/pipermail/package-announce/2012-January/071627.html