-----BEGIN PRIVACY-ENHANCED MESSAGE----- Proc-Type: 4,MIC-CLEAR Content-Domain: RFC822 Originator-Certificate: MIICozCCAgwCAREwDQYJKoZIhvcNAQECBQAwgYYxC zAJBgNVBAYTAlVTMSswKQYDVQQKEyJEZWZlbnNlIEluZm9ybWF0aW9uIFN5c3Rlb XMgQWdlbmN5MTAwLgYDVQQLEydDZW50ZXIgZm9yIEluZm9ybWF0aW9uIFN5c3Rlb XMgU2VjdXJpdHkxGDAWBgNVBAsTD0NvdW50ZXJtZWFzdXJlczAeFw05MzEyMDkxO DU5MTZaFw05NTEyMDkxODU5MTZaMIGxMQswCQYDVQQGEwJVUzErMCkGA1UEChMiR GVmZW5zZSBJbmZvcm1hdGlvbiBTeXN0ZW1zIEFnZW5jeTEwMC4GA1UECxMnQ2Vud GVyIGZvciBJbmZvcm1hdGlvbiBTeXN0ZW1zIFNlY3VyaXR5MRgwFgYDVQQLEw9Db 3VudGVybWVhc3VyZXMxEzARBgNVBAsTCk9wZXJhdGlvbnMxFDASBgNVBAMTC1Bld GUgSGFtbWVzMIGaMAoGBFUIAQECAgQAA4GLADCBhwKBgQDFFJkcaDOuS+6Ai2vmT bwY6JRbhdzPsl6X60hnXruOw2WvrAhc8BTFB+id75m3M55i+Th6MxWH20QHyQq5u yVghOu/s37OxIrj7irNPjtUdPv8b2m4hNGEW53QH6GmXkxLmgLzOhookpoYPC+uw 2MzibDnleVI50d2m//XsWs7hwIBAzANBgkqhkiG9w0BAQIFAAOBgQDHH6CmBoyWU zPlqVnEWYKIBsifqdTJzkKfnoST7NDRIakUP49FP86Cyy1+2AKpUCWaxjq+wGHCH RCNFCCrOwdC9z8XwJal/c69ml6eLRhOoX77ANndpU9E5+eHxP+6Ute6lc63K7+Lz 5xOULjmgaMmKDkTXveVcQO6R2CTY37vcA== Issuer-Certificate: MIICNTCCAZ4CASIwDQYJKoZIhvcNAQECBQAwRDELMAkGA 1UEBhMCVVMxCzAJBgNVBAgTAk1EMSgwJgYDVQQKEx9UcnVzdGVkIEluZm9ybWF0a W9uIFN5c3RlbXMgUENBMB4XDTk0MDIyNTE0NDkxMloXDTk0MDMwNzE0NDkxMlowg YYxCzAJBgNVBAYTAlVTMSswKQYDVQQKEyJEZWZlbnNlIEluZm9ybWF0aW9uIFN5c 3RlbXMgQWdlbmN5MTAwLgYDVQQLEydDZW50ZXIgZm9yIEluZm9ybWF0aW9uIFN5c 3RlbXMgU2VjdXJpdHkxGDAWBgNVBAsTD0NvdW50ZXJtZWFzdXJlczCBmjAKBgRVC AEBAgIEAAOBiwAwgYcCgYEA19l6BN7iTGYEU61qJETIjBh3iAeHzoL8sZ5KwFRZD S/a1KnYlD1zJHR/KeQCOBWW2HzX43TFLCNGU7UD9i6m8AymLe5IJf/bGh0Rne7Jd Q1GAOLw7/J4hE57IMbGETZpzeU1D9IYxiERRNio/oa422lUlS9JZHLA5jaPNcUrX P8CAQMwDQYJKoZIhvcNAQECBQADgYEApkliqAdudoOxvOFmQkOZbSgtlpn61VcNC R7azDNJa2ulevaebptwSTs2OvMeuR/J0Ez4TC7XrJXLVjI5huRAqc+EWGRpZYRMa CARZyE7gGYjUqS7DIQazfskeWiB8zheyW5tCVn+jnB09AZXtgbM6qRjyqrmSdCpg CtfgazIKqI= Issuer-Certificate: MIIB8jCCAVsCAQEwDQYJKoZIhvcNAQECBQAwRDELMAkGA 1UEBhMCVVMxCzAJBgNVBAgTAk1EMSgwJgYDVQQKEx9UcnVzdGVkIEluZm9ybWF0a W9uIFN5c3RlbXMgUENBMB4XDTkzMDUyODE3MTEyN1oXDTk1MDUyODE3MTEyN1owR DELMAkGA1UEBhMCVVMxCzAJBgNVBAgTAk1EMSgwJgYDVQQKEx9UcnVzdGVkIEluZ m9ybWF0aW9uIFN5c3RlbXMgUENBMIGaMAoGBFUIAQECAgQAA4GLADCBhwKBgQDbL xaRlS3u54yyRgVDI5dcE9nlasL8fJqOGlyo7xH2FZnr3kUfsFj7OGiYsr6UbvqwK nyfMIRUrXDUa64leGmft3SK27psDUHOynRSCc40d/HrDf810U5tnTamBKUIMqivK 4GoL0tMRA1eX6hALAvLLgK1HbnwZAo6GqQGW8CIJQIBAzANBgkqhkiG9w0BAQIFA AOBgQDBp5aC6oV6IuFi8JCctq57bew604HHNllgjjp7zdXafq6jctRg2g91k/yFW h19bJC/tNrb0WVwuZOs5L/FToPMNIIHzaW/YSROBmyhTDYaKHZGj0P1+iNjMbHt9 dm1QEHGIfKgBwFidItnOa74DfkXdijlPRnr/+E2Ib6PM+hEfQ== MIC-Info: RSA-MD5,RSA,qbxIcAMZPWKRLI5ACIxBuIl6LAzl9m8GH9dvMCg3knP qdHwts+G1ql9nHUKrSraJ30iiC4eVjtysgU6kapVhuSwakcJeA+O8597sSvKV7bS wX09SEdWnhntHbcyQiNf5iG+s+3M3RQxDbLa3IWFFRYNpA1W5VEARbL21Ez9XN/4 = <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Automated Systems Security Incident Support Team _____ ___ ___ _____ ___ _____ | / /\ / \ / \ | / \ | | / Integritas / \ \___ \___ | \___ | | < et /____\ \ \ | \ | | \ Celeritas / \ \___/ \___/ __|__ \___/ | |_____\ <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bulletin 94-41 Release date: 23 December 1994, 10:30 AM EST (GMT -4) SUBJECT: NFS Vulnerabilities. SUMMARY: Increase in reports of root compromises caused by intruders using tools to exploit a number of Network File System (NFS) vulnerabilities. BACKGROUND: There are tools being used by intruders to exploit a number of NFS vulnerabilities and gain unauthorized access to network resources. These tools and related information have been widely distributed on numerous Internet forums. IMPACT: Varies depending on vulnerabilities present. In the worst case users can gain unauthorized root access from a remote host. RECOMMENDED SOLUTION: A. Filter packets at your firewall/router. Filter TCP port 111, UDP port 111 (portmapper), TCP port 2049, and UDP port 2049 (nfsd). Consult your vendor or your firewall documentation for detailed instructions on how to configure these ports. These measures will prevent access to NFS at your site from outside your firewall, but it will not protect you from attacks launched from your local network, from behind your firewall. B. Use a portmapper that disallows proxy access. Be sure that you do this for every host that runs a portmapper. For Solaris, 2.x, use a version of rpcbind that disallows proxy access. A portmapper that disallows proxy access protects all hosts with the modified portmapper from attacks that originate either inside or outside your firewall. Because this security measure addresses only the portmapper vulnerability, we recommend combining it with measure A above. Wietse Venema has developed a portmapper that disallows proxy access. It is available by anonymous FTP from ftp.win.tue.nl:/pub/security/portmap_3.shar.Z assist.mil:/pub/tools/NFStools/portmap_3.shar.Z MD5 checksum: f6a3ad98772e7a402ddcdac277adc4a6 For Solaris systems, Venema has developed a version of rpcbind that does not allow proxy access. Solaris users should install this program, not the portmapper. Rpcbind is available by anonymous FTP from the same sites as the portmapper: ftp.win.tue.nl:/pub/security/rpcbind_1.1.tar.Z assist.mil:/pub/tools/NFStools/rpcbind_1.1.tar.Z MD5 checksum: 58437adcbea0a55e37d3a3211f72c08b C. Check the configuration of the /etc/exports files on your hosts. In particular: 1. Do *not* self-reference an NFS server in its own exports file. 2. Do not allow the exports file to contain a "localhost" entry. 3. Export file systems only to hosts that require them. 4. Export only to fully qualified hostnames. 5. Ensure that export lists do not exceed 256 characters. If you have aliases, the list should not exceed 256 characters *after* the aliases have been expanded. (See ASSIST Bulletin 94-03, Revised Patch for SunOS /usr/etc/rpc.mountd Vulnerability.) 6. Use the showmount(8) utility to check that exports are correct. 7. Wherever possible, mount file systems to be exported read only and export file systems read only. D. Ensure that your systems are current with patches and workarounds available from your vendor and identified in ASSIST bulletins. The following advisories address problems related to NFS: ASSIST Bulletin 92-30, Security problem in SunOS fsirand program ASSIST Bulletin 92-37, Revised patch for SunOS /usr/etc/rpc.mountd vulnerabilitity ASSIST Bulletin 92-56, Multiple SunOS vulnerabilities patched ASSIST Bulletin 93-22, Summary of SunOS and Solaris security patches. ASSIST Bulletin 94-03, Revised Patch for SunOS /usr/etc/rpc.mountd vulnerability Vendors may have additional patches not covered by this or previous bulletins, contact your vendor if you need additional information about vulnerabilities and patches. ASSIST would like to thank the CERT Coordination Center,Steve Bellovin, Casper Dik, Leendert van Doorn, and Wietse Venema for information contained in this bulletin. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ASSIST is an element of the Defense Information Systems Agency (DISA), Center for Information Systems Security (CISS), that provides service to the entire DoD community. Constituents of the DoD with questions about ASSIST or computer security security issues, can contact ASSIST using one of the methods listed below. Non-DoD organizations/institutions, contact the Forum of Incident Response and Security Teams (FIRST) (FIRST) representative. To obtain a list of FIRST member organizations and their constituencies send an email to docserver@first.org with an empty "subject" line and a message body containing the line "send first-contacts". ASSIST Information Resources: To be included in the distribution list for the ASSIST bulletins, send your Milnet (Internet) e-mail address to assist-request@assist.mil. Back issues of ASSIST bulletins, and other security related information, are available from the ASSIST BBS at 703-756-7993/1154 DSN 289-7993/1154, and through anonymous FTP from assist.mil (IP address 199.211.123.11). Note: assist.mil will only accept anonymous FTP connections from Milnet addresses that are registered with the NIC or DNS. ASSIST Contact Information: PHONE: 800-357-4231 (or 703-756-7974 DSN 289), duty hours are 06:00 to 22:30 EDT (GMT -4) Monday through Friday. During off duty hours, weekends and holidays, ASSIST can be reached via pager at 800-791- 4857. The page will be answered within 30 minutes, however if a quicker response is required, prefix the phone number with "999". ELECTRONIC MAIL: Send to assist@assist.mil. ASSIST BBS: Leave a message for the "sysop". Privacy Enhanced Mail (PEM): ASSIST uses PEM, a public key encryption tool, to digitally sign all bulletins that are distributed through e-mail. The section of seemingly random characters between the "BEGIN PRIVACY-ENHANCED MESSAGE" and "BEGIN ASSIST BULLETIN" contains machine-readable digital signature information generated by PEM, not corrupted data. PEM software for UNIX systems is available from Trusted Information Systems (TIS) at no cost, and can be obtained via anonymous FTP from ftp.tis.com (IP 192.94.214.96). Note: The TIS software is just one of several implementations of PEM currently available and additional versions are likely to be offered from other sources in the near future. Reference herein to any specific commercial product, process, or service by trade name, trademark manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by ASSIST. The views and opinions of authors expressed herein shall not be used for advertising or product endorsement purposes. -----END PRIVACY-ENHANCED MESSAGE-----