INFORMATION BULLETIN INFORMATION BULLETIN April 2, 2001 19:00 GMT
Revised September 17, 2001 19:00 GMT
PROBLEM: A buffer overflow exists in the snmpXdmid code. Local and
remote users can exploit the buffer overflow.
PLATFORM: Any machine running Solaris 2.6, 7, or 8 with snmpXdmid
installed and enabled. SnmpXdmid is installed and enabled by
default on these systems.
DAMAGE: Through the exploitation a buffer overflow in the translation
of DMI indications to SNMP events, root compromise is attainable.
SOLUTION: The advisory offers the following solutions:
A. Apply the patch from Sun.
B. Disable snmpXdmi.
C. Restrict access to snmpXdmi and other RPC services.
It is important to note that if not implemented properly,
the 'restrict access' method can leave a system vulnerable.
VULNERABILITYThe risk is HIGH. This vulnerability is publicly known. ASSESSMENT:
[Revised 9/17/2001 - Added link to sun patches.]
[****** Begin CERT Advisory ******]
CERT Advisory CA-2001-05 Exploitation of snmpXdmid
Original release date: March 30, 2001
Source: CERT/CC
A complete revision history can be found at the end of this file.
Systems Affected
Any machine running Solaris 2.6, 7, or 8 with snmpXdmid installed and
enabled. snmpXdmid is installed and enabled by default on these
systems.
Overview
The CERT/CC has received numerous reports indicating that a
vulnerability in snmpXdmid is being actively exploited. Exploitation
of this vulnerability allows an intruder to gain privileged (root)
access to the system.
I. Description
The SNMP to DMI mapper daemon (snmpXdmid) translates Simple Network
Management Protocol (SNMP) events to Desktop Management Interface
(DMI) indications and vice-versa. Both protocols serve a similar
purpose, and the translation daemon allows users to manage devices
using either protocol. The snmpXdmi daemon registers itself with the
snmpdx and dmid daemons, translating and forwarding requests from one
daemon to the other.
snmpXdmid contains a buffer overflow in the code for translating DMI
indications to SNMP events. This buffer overflow is exploitable by
local or remote intruders to gain root privileges.
More information about this vulnerability can be found in
CERT/CC Vulnerability Note VU#648304
Sun Solaris DMI to SNMP mapper daemon snmpXdmid contains buffer overflow
http://www.kb.cert.org/vuls/id/648304
Affected sites have reported discovering the following things on
compromised systems:
* Evidence of extensive scanning for RPC services (port
111/{udp,tcp}) with explicit requests for the snmpXdmid service
port prior to the exploit attempt
* A core file from snmpXdmid on the / partition
* An additional copy of inetd running (possibly using /tmp/bob as a
configuration file)
* A root-privileged telnet backdoor installed and listening on port
2766 (although any port could be used)
* An SSH backdoor installed and listening on port 47018 (although
any port could be used)
* An IRC proxy installed as /var/lp/lpacct/lpacct and listening on
port 6668
* A sniffer installed as /usr/lib/lpset
* Logs altered to hide evidence of the compromise
* System binaries replaced by a rootkit installed in /dev/pts/01/
and /dev/pts/01/bin (the versions of 'ls' and 'find' installed
by the rootkit do not show these directories)
The contents of /dev/pts/01 may include
+ bin
+ crypt
+ idsol
+ patcher
+ su-backup
+ utime
+ bnclp
+ idrun
+ l3
+ pg
+ urklogin
The contents of /dev/pts/01/bin may include
+ du
+ find
+ ls
+ netstat
+ passwd
+ ping
+ psr
+ sparcv7
+ su
Note: Since 'ps' and 'netstat' are both replaced by the rootkit, they
will not show these processes or open ports. However, you may find
that '/usr/ucb/ps' is still intact, and will show the additional
processes.
II. Impact
A local or remote user that is able to send packets to the snmpXdmi
daemon on a system may gain root privileges.
III. Solution
* Apply a patch from Sun when it is available
Sun has been notified of this issue and is actively working on
patches to address the problem. This advisory will be updated when
patches are available.
*****See below, patches available*****
* Disable snmpXdmi
Until patches are available, sites that do not use both SNMP and
DMI are stongly encouraged to disable snmpXdmid.
One way to accomplish this is to issue the following commands (as
root):
1. Prevent the daemon from starting up upon reboot
mv /etc/rc3.d/SXXdmi /etc/rc3.d/KXXdmi
2. Killing the currently running daemon
/etc/init.d/init.dmi stop`
3. Verify that the daemon is no longer active
ps -ef | grep dmi
4. As an additional measure, you may wish to make the daemon
non-executable
chmod 000 /usr/lib/dmi/snmpXdmid
* Restrict access to snmpXdmi and other RPC services
For sites that require the functionality of snmpXdmi or other RPC
services, local IP filtering rules that prevent hosts other than
localhost from connecting to the daemon may mitigate the risks
associated with running the daemon. Sun RPC services are advertised on
port 111/{tcp,udp}. The snmpXdmid RPC service id is 100249; use
'rpcinfo -p' to list local site port bindings:
# rpcinfo -p | grep 100249
100249 1 udp 32785
100249 1 tcp 32786
Note that site-specific port binding will vary.
Appendix A. - Vendor Information
Sun Microsystems
We can confirm that this affects all versions of Solaris that ship the
SNMP to DMI mapper daemon, that is, Solaris 2.6, 7 and 8. To the best
of my understanding from discussion with the engineering group working
on this, for sites which do use DMI (dmispd) and the mapper
(snmpXdmid), there are no workarounds.
______________________________________________________________________
The CERT/CC thanks Job de Haas (job@itsx.com) of ITSX BV Amsterdam,
The Netherlands (http://www.itsx.com) for reporting this vulnerability
to the CERT/CC.
______________________________________________________________________
This document was written by Brian B. King with significant
contributions by Jeff Havrilla, and Cory F. Cohen.
______________________________________________________________________
This document is available from:
http://www.cert.org/advisories/CA-2001-05.html
______________________________________________________________________
CERT/CC Contact Information
Email: cert@cert.org
Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
Postal address:
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Software Engineering Institute
Carnegie Mellon University
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U.S.A.
CERT personnel answer the hotline 08:00-20:00 EST(GMT-5) / EDT(GMT-4)
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______________________________________________________________________
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_________________________________________________________________
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Copyright 2001 Carnegie Mellon University.
Revision History
March 30, 2001: Initial release
[****** End CERT Advisory ******]
According to Sun bulletin #00207 8/30/2001 sun patches are available for Solaris 2.6, 2.7, and 2.8.
| OS Version | Patch ID |
| SunOS 5.8 | 108869-07 |
| SunOS 5.8_x86 | 108870-07 |
| SunOS 5.7 | 107709-15 |
| SunOS 5.7_x86 | 107710-15 |
| SunOS 5.6 | 106787-15 |
| SunOS 5.6_x86 | 106872-15 |
Patches listed in this bulletin are available to all Sun customers at:
http://sunsolve.sun.com/securitypatch
Checksums for the patches listed in this bulletin are available at:
ftp://sunsolve.sun.com/pub/patches/CHECKSUMS
CIAC wishes to acknowledge the contributions of CERT for the information contained in this bulletin.
Voice: +1 925-422-8193 (7 x 24)
FAX: +1 925-423-8002
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