TUCoPS :: Malware :: al200105.txt

AusCERT Alert 2001.05 New Bind worm: 1i0n


A  U  S  C  E  R  T                                           A  L  E  R  T

                        AL-2001.05  --  AUSCERT ALERT
                 SANS Institute ALERT - New Bind worm: 1i0n
                                26 March 2001


        AusCERT Alert Summary

Product:                bind 8.2
                        bind 8.2-P1
                        bind 8.2.1
                        bind 8.2.2-Px
                        bind 8.2.3-betas
Vendor:                 ISC
Impact:                 Execute Arbitrary Code/Commands
                        Root Compromise
Access Required:        Remote

Ref:                    AA-2001.01


The message included below is an alert issued by the SANS Institute
regarding a new bind worm "1i0n".  AusCERT has received reports of
compromises involving this worm which exploits particular bind
vulnerabilities outlined in AUSCERT Advisory AA-2001.01 - ISC BIND
Vulnerability released 31 January 2001.

AusCERT is issuing this external security bulletin as an AusCERT Alert to
emphasize the significance of the potential impact of the 1i0n worm and
the vulnerabilities outlined in AA-2001.01.  For details on detection and
removal, refer to the SANS Alert included below.  More information about
these vulnerabilities and the availability of updated vendor software
packages is available in recent AusCERT External Security Bulletins and

        AusCERT Alert AA-2001.01 - ISC BIND Vulnerability

        CERT Advisory CA-2001-02 - Multiple Vulnerabilities in BIND

        RHSA-2001:007-03 - Updated bind packages available

        Internet Security Systems Security Alert - Remote Vulnerabilities   
        in BIND versions 4 and 8

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Hash: SHA1


March 23, 2001 7:00 AM

Late last night, the SANS Institute (through its Global Incident
Analysis Center) uncovered a dangerous new worm that appears to be
spreading rapidly across the Internet.  It scans the Internet looking
for Linux computers with a known vulnerability. It infects the
vulnerable machines, steals the password file  (sending it to a
China.com site), installs other hacking tools, and forces the newly
infected machine to begin scanning the Internet looking for other

Several experts from the security community worked through the night to
decompose the worm's code and engineer a utility to help you discover
if the Lion worm has affected your organization.

Updates to this announcement will be posted at the SANS web site,


The Lion worm is similar to the Ramen worm. However, this worm is
significantly more dangerous and should be taken very seriously.  It
infects Linux machines running the BIND DNS server.  It is known to
infect bind version(s) 8.2, 8.2-P1, 8.2.1, 8.2.2-Px, and all
8.2.3-betas. The specific vulnerability used by the worm to exploit
machines is the TSIG vulnerability that was reported on January 29,

The Lion worm spreads via an application called "randb".  Randb scans
random class B networks probing TCP port 53. Once it hits a system, it
checks to see if it is vulnerable. If so, Lion exploits the system using
an exploit called "name".  It then installs the t0rn rootkit.

Once Lion has compromised a system, it:

- - - Sends the contents of /etc/passwd, /etc/shadow, as well as some
network settings to an address in the china.com domain.
- - - Deletes /etc/hosts.deny, eliminating the host-based perimeter
protection afforded by tcp wrappers.
- - - Installs backdoor root shells on ports 60008/tcp and 33567/tcp (via
inetd, see /etc/inetd.conf)
- - - Installs a trojaned version of ssh that listens on 33568/tcp
- - - Kills Syslogd , so the logging on the system can't be trusted
- - - Installs a trojaned version of login
- - - Looks for a hashed password in /etc/ttyhash
- - - /usr/sbin/nscd (the optional Name Service Caching daemon) is
overwritten with a trojaned version of ssh.

The t0rn rootkit replaces several binaries on the system in order to
stealth itself. Here are the binaries that it replaces:

du, find, ifconfig, in.telnetd, in.fingerd, login, ls, mjy, netstat,
ps, pstree, top

- - - "Mjy" is a utility for cleaning out log entries, and is placed in /bin
and /usr/man/man1/man1/lib/.lib/.
- - - in.telnetd is also placed in these directories; its use is not known
at this time.  
- - - A setuid shell is placed in /usr/man/man1/man1/lib/.lib/.x


We have developed a utility called Lionfind that will detect the Lion
files on an infected system.  Simply download it, uncompress it, and
run lionfind.  This utility will list which of the suspect files is on
the system.

At this time, Lionfind is not able to remove the virus from the system.
If and when an updated version becomes available (and we expect to
provide one), an announcement will be made at this site.

Download Lionfind at http://www.sans.org/y2k/lionfind-0.1.tar.gz


Further information can be found at:

http://www.cert.org/advisories/CA-2001-02.html, CERT Advisory CA-2001-02,
Multiple Vulnerabilities in BIND
http://www.kb.cert.org/vuls/id/196945 ISC BIND 8 contains buffer overflow
in transaction signature (TSIG) handling code
http://www.sans.org/y2k/t0rn.htm Information about the t0rn rootkit.
The following vendor update pages may help you in fixing the original BIND

Redhat Linux RHSA-2001:007-03 - Bind remote exploit
Debian GNU/Linux DSA-026-1 BIND
SuSE Linux SuSE-SA:2001:03 - Bind 8 remote root compromise.
http://www.suse.com/de/support/security/2001_003_bind8_ txt.txt
Caldera Linux CSSA-2001-008.0 Bind buffer overflow

This security advisory was prepared by Matt Fearnow of the SANS
Institute and William Stearns of the Dartmouth Institute for Security
Technology Studies.

The Lionfind utility was written by William Stearns. William is an
Open-Source developer, enthusiast, and advocate from Vermont, USA. His
day job at the Institute for Security Technology Studies at Dartmouth
College pays him to work on network security and Linux projects.

Also contributing efforts go to Dave Dittrich from the University of
Washington, and Greg Shipley of Neohapsis

Matt Fearnow
SANS GIAC Incident Handler

If you have additional data on this worm or a critical quetsion  please
email lionworm@sans.org
Version: GnuPG v1.0.4 (BSD/OS)
Comment: For info see http://www.gnupg.org


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This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content.  The decision to use any or all of this information is
the responsibility of each user or organisation, and should be done so in
accordance with site policies and procedures.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the original authors to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:


If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security

Internet Email: auscert@auscert.org.au
Facsimile:	(07) 3365 7031
Telephone:	(07) 3365 4417 (International: +61 7 3365 4417)
		AusCERT personnel answer during Queensland business hours
		which are GMT+10:00 (AEST).
		On call after hours for emergencies.

Version: 2.6.3i
Charset: noconv
Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key


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