__________________________________________________________
The U.S. Department of Energy
Computer Incident Advisory Capability
___ __ __ _ ___
/ | /_\ /
\___ __|__ / \ \___
__________________________________________________________
INFORMATION BULLETIN
NXT BIND 8.2.x Overflow Vulnerability
June 13, 2000 13:00 GMT Number K-050
______________________________________________________________________________
PROBLEM: BIND versions 8.2, 8.2.1 and 8.2.2 will allow a buffer overflow
condition, resulting in illegal remote access.
PLATFORM: Red Hat, Solaris, FreeBSD, OpenBSD, NetBSD, Slackware.
DAMAGE: A remote user will be able to gain root on the DNS server.
SOLUTION: Upgrade BIND to version 8.2.2-P2. Preferably upgrade to the
latest version 8.2.2-P5.
______________________________________________________________________________
VULNERABILITY The risk is HIGH. The exploit is publicly available.
ASSESSMENT:
______________________________________________________________________________
Please note that older versions of BIND are not included in this discussion
of the NXT Buffer Overflow vulnerability. There are security issues with
older releases and should be upgraded to the latest release - 8.2.2-P5. If
it is not possible to upgrade from version 4.x, for whatever reason, it is
recommended that 4.9.7 be used.
Scanning activity has increased on port 53 (named service). The scans are
looking for systems running BIND version 8.2, 8.2.1 or 8.2.2. These versions
of BIND are known to be on released versions of:
Slackware 7.0
Red Hat 6.0, 6.1
Solaris 2.6, 2.7
Caldera OpenLinux 2.2
FreeBSD 3.2
OpenBSD 2.5
NetBSD 1.4.1
To determine the version of BIND running on a server type:
dig @<IP ADDRESS> version.bind chaos txt
on any UNIX machine with the dig command installed. The output of the dig
command will look like the following:
; <<>> DiG 8.2 <<>> @127.0.0.1 version.bind chaos txt
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUERY SECTION:
;; version.bind, type = TXT, class = CHAOS
;; ANSWER SECTION:
VERSION.BIND. 0S CHAOS TXT "8.2.2-P5"
;; Total query time: 4 msec
;; FROM: computer to SERVER: 127.0.0.1
;; WHEN: Tue Jun 13 06:28:22 2000
;; MSG SIZE sent: 30 rcvd: 63
Inside the ;; ANSWER SECTION is the version of BIND running on the server.
How the exploit works
The exploit requires two systems to be successful. The first is a DNS server
that will have an altered DNS table. The second machine is where the attack
will take place.
Intruders alter a valid DNS server's (we will call this box [SERVER 1]) lookup
table to point toward their computer [hacker.com] as the Authoritative Name
Server for that domain. Intruders then prompt your DNS server to resolve
[hacker.com]. [SERVER 1] passes the information back to your DNS server
for the Authoritative Name Server for [hacker.com]. Your DNS server then goes
to [hacker.com] looking to complete the query. Once your DNS server queries
[hacker.com] for resolution, BIND runs and the buffer overflow condition
occurs.
Once the buffer overflow is executed, the following command is executed in the
source code obtained by CIAC: cd /; uname -a; pwd; id;. The named service
will crash as a result of the buffer overflow.
To get the latest release of BIND (8.2.2-P5), go to:
http://www.isc.org/products/BIND/bind8.html
The following vendor patches are available as of May 25, 2000:
Red Hat Linux 6.x:
Intel:
ftp://updates.redhat.com/6.1/i386/bind-8.2.2_P3-1.i386.rpm
ftp://updates.redhat.com/6.1/i386/bind-devel-8.2.2_P3-1.i386.rpm
ftp://updates.redhat.com/6.1/i386/bind-utils-8.2.2_P3-1.i386.rpm
Alpha:
ftp://updates.redhat.com/6.0/alpha/bind-8.2.2_P3-1.alpha.rpm
ftp://updates.redhat.com/6.0/alpha/bind-devel-8.2.2_P3-1.alpha.rpm
ftp://updates.redhat.com/6.0/alpha/bind-utils-8.2.2_P3-1.alpha.rpm
Sparc:
ftp://updates.redhat.com/6.0/sparc/bind-8.2.2_P3-1.sparc.rpm
ftp://updates.redhat.com/6.0/sparc/bind-devel-8.2.2_P3-1.sparc.rpm
ftp://updates.redhat.com/6.0/sparc/bind-utils-8.2.2_P3-1.sparc.rpm
Source packages:
ftp://updates.redhat.com/6.1/SRPMS/bind-8.2.2_P3-1.src.rpm
Caldera
ftp://ftp.calderasystems.com/pub/OpenLinux/updates/2.3/current
SlackWare 7.0:
ftp.cdrom.com:/pub/linux/slackware-7.0/patches/bind.tgz
Sun Solaris 7.0_x86:
Sun patch 107019-02
Sun patch 106939-03
Sun Solaris 7.0:
Sun patch 107018-02
Sun patch 106938-03
_______________________________________________________________________________
CIAC wishes to acknowledge the contributions of Security Focus for information
contained in this bulletin.
_______________________________________________________________________________
CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.
CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
Voice: +1 925-422-8193
FAX: +1 925-423-8002
STU-III: +1 925-423-2604
E-mail: ciac@llnl.gov
For emergencies and off-hour assistance, DOE, DOE contractor sites,
and the NIH may contact CIAC 24-hours a day. During off hours (5PM -
8AM PST), use one of the following methods to contact CIAC:
1. Call the CIAC voice number 925-422-8193 and leave a message, or
2. Call 888-449-8369 to send a Sky Page to the CIAC duty person or
3. Send e-mail to 4498369@skytel.com, or
4. Call 800-201-9288 for the CIAC Project Leader.
Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.
World Wide Web: http://www.ciac.org/
(or http://ciac.llnl.gov -- they're the same machine)
Anonymous FTP: ftp.ciac.org
(or ciac.llnl.gov -- they're the same machine)
Modem access: +1 (925) 423-4753 (28.8K baud)
+1 (925) 423-3331 (28.8K baud)
PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins. If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.
This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
legal liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial products,
process, or service by trade name, trademark, manufacturer, or
otherwise, does not necessarily constitute or imply its endorsement,
recommendation or favoring by the United States Government or the
University of California. The views and opinions of authors expressed
herein do not necessarily state or reflect those of the United States
Government or the University of California, and shall not be used for
advertising or product endorsement purposes.
LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC)
K-039: VBS.LoveLetter.A Worm
K-040: Netscape Navigator Improperly Validates SSL Sessions
K-041: Denial of Service and File Reading Vulnerabilities
K-042: Microsoft "Office 2000 UA Control" Vulnerability
K-043: Buffer Overrun Vulnerabilities in Kerberos
K-044: Microsoft: Vulnerabilities in Internet Explorer
K-045: SGI Vulnerability in infosrch.cgi
K-046: 386-BSD Based Operating Systems - IPCS Vulnerability
K-048: Permissions Problems with FrontPage Extensions
K-049: Microsoft IE "SSL Certificate Validation" Vulnerability