Stolen Program Easily Cracks BSD Servers - Other Unix OS vulnerable

A free operating system used by thousands of Web sites has a serious new security hole that is being exploited by hackers, according to the developers of FreeBSD. An advisory released Monday by FreeBSD.org says that a bug in the Telnet program included with FreeBSD and related operating systems can allow remote attackers to gain complete control of the Web server.

A listing at the FreeBSD site reveals that the operating system is used by high-profile companies including Yahoo, Sony and Microsoft's Hotmail. The Telnet daemon is enabled by default on all FreeBSD installations, "and is being actively exploited in the wild," according to the advisory. Telnet is an Internet protocol that allows a computer user to log onto another computer terminal remotely. The program commonly is used by administrators to remotely control Web servers....

Stolen Program Cracks BSD Servers
By Brian McWilliams, Newsbytes
BERLIN, GERMANY,
24 Jul 2001, 12:16 PM CST

FreeBSD's "Telnetd" buffer overflow vulnerability was discovered by a group
of network security enthusiasts called Teso. The group posted a description of the bug to
Bugtraq, a security mailing list, on July 18.

While Teso did not publicly release a program that exploits the hole, a member of the
group told Newsbytes it has written such a tool. The exploit was subsequently
"stolen," according to the member, and posted today to several security mailing
lists.

Teso told Newsbytes the stolen tool is already in widespread use by computer attackers,
a development that forced the group to release its advisory to the public even through a
security patch was not yet available.

Statistics from the Safemode security information site show that several Web servers
running FreeBSD were defaced by attackers in recent months. The compromised servers
include FreeBSD's own site, as well as that of TiVo Inc., the SANS Institute, Themes.org,
and a Microsoft site in Belgium.

According to the Teso advisory, other UNIX operating systems also based on code from
Berkeley Software Design Inc., including BSDi and NetBSD, are vulnerable to the Telnetd
exploit as well.

FreeBSD has released a patch to correct the problem. As a temporary workaround, system
operators can disable the Telnet service, according to FreeBSD.org.

The Teso advisory on Telnetd is online at http://www.team-teso.net/advisories.php
.

The FreeBSD advisory is viewable at http://groups.google.com/groups?hl=en&safe=off&thì6e7f197404d6b3,1
.